id
int64
problem_number
string
title
string
statement
string
background
string
difficulty_level_id
int64
status
string
proposed_by
string
proposed_year
int64
category_id
int64
set_id
int64
view_count
int64
favorite_count
int64
created_at
timestamp[s]
updated_at
timestamp[s]
published
bool
category
dict
difficulty
dict
set
dict
duplicates
list
status_review
unknown
archive_reason
string
duplicate_of
list
old_problem_number
string
notes
string
tags
list
literature_assessment
string
literature_sources
list
literature_checked_at
timestamp[s]
solution_reference
string
source_url
string
source
string
prize
string
references
list
clean_statement
string
original_statement
string
statement_status
string
statement_verification
string
research_classification
string
research_summary
string
research_difficulty_suggested
string
historical_research_summary
string
research_summary_reviewed_at
timestamp[s]
source_citation
string
30,006,716
EP-85
Erdős Problem #85: Graph Theory, Ramsey Theory
Let $n\geq 4$ and $f(n)$ be minimal such that every graph on $n$ vertices with minimal degree $\geq f(n)$ contains a $C_4$. Is it true that, for all large $n$, $f(n+1)\geq f(n)$?
Erdős Problems (#85, https://www.erdosproblems.com/85). Maintainer status: OPEN. OEIS: A006672. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.85).
3
open
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/85", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "open" }
null
null
null
null
[ "erdos-problems", "graph-theory", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/85
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,717
EP-88
Erdős Problem #88: Graph Theory, Ramsey Theory
For any $\epsilon>0$ there exists $\delta=\delta(\epsilon)>0$ such that if $G$ is a graph on $n$ vertices with no independent set or clique of size $\geq \epsilon\log n$ then $G$ contains an induced subgraph with $m$ edges for all $m\leq \delta n^2$.
Erdős Problems (#88, https://www.erdosproblems.com/88). Maintainer status: PROVED. Erdős prize: $100. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.88).
3
solved
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/88", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "graph-theory", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/88
Erdős Problems (erdosproblems.com)
$100
[]
null
null
null
null
null
null
null
null
null
null
30,006,718
EP-93
Erdős Problem #93: Geometry, Convex
If $n$ distinct points in $\mathbb{R}^2$ form a convex polygon then they determine at least $\lfloor \frac{n}{2}\rfloor$ distinct distances.
Erdős Problems (#93, https://www.erdosproblems.com/93). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.93).
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/93", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "geometry", "convex", "distances" ]
null
null
null
null
https://www.erdosproblems.com/93
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,719
EP-94
Erdős Problem #94: Geometry, Convex
Suppose $n$ points in $\mathbb{R}^2$ determine a convex polygon and the set of distances between them is $\{u_1,\ldots,u_t\}$. Suppose $u_i$ appears as the distance between $f(u_i)$ many pairs of points. Then\[\sum_i f(u_i)^2 \ll n^3.\]
Erdős Problems (#94, https://www.erdosproblems.com/94). Maintainer status: PROVED (LEAN). Erdős prize: £25. OEIS: A387858. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.94).
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/94", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "geometry", "convex", "distances" ]
null
null
null
null
https://www.erdosproblems.com/94
Erdős Problems (erdosproblems.com)
£25
[]
null
null
null
null
null
null
null
null
null
null
30,006,720
EP-95
Erdős Problem #95: Geometry, Convex
Let $x_1,\ldots,x_n\in\mathbb{R}^2$ determine the set of distances $\{u_1,\ldots,u_t\}$. Suppose $u_i$ appears as the distance between $f(u_i)$ many pairs of points. Then for all $\epsilon>0$\[\sum_i f(u_i)^2 \ll_\epsilon n^{3+\epsilon}.\]
Erdős Problems (#95, https://www.erdosproblems.com/95). Maintainer status: PROVED (LEAN). Erdős prize: $500. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.95).
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/95", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "geometry", "convex", "distances" ]
null
null
null
null
https://www.erdosproblems.com/95
Erdős Problems (erdosproblems.com)
$500
[]
null
null
null
null
null
null
null
null
null
null
30,006,721
EP-97
Erdős Problem #97: Geometry, Distances
Does every convex polygon have a vertex with no other $4$ vertices equidistant from it?
Erdős Problems (#97, https://www.erdosproblems.com/97). Maintainer status: FALSIFIABLE. Erdős prize: $100. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.97).
3
open
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/97", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "falsifiable" }
null
null
null
null
[ "erdos-problems", "geometry", "distances", "convex" ]
null
null
null
null
https://www.erdosproblems.com/97
Erdős Problems (erdosproblems.com)
$100
[]
null
null
null
null
null
null
null
null
null
null
30,006,722
EP-105
Erdős Problem #105: Geometry
Let $A,B\subset \mathbb{R}^2$ be disjoint sets of size $n$ and $n-3$ respectively, with not all of $A$ contained on a single line. Is there a line which contains at least two points from $A$ and no points from $B$?
Erdős Problems (#105, https://www.erdosproblems.com/105). Maintainer status: DISPROVED (LEAN). Erdős prize: $50. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.105).
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/105", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "geometry" ]
null
null
null
null
https://www.erdosproblems.com/105
Erdős Problems (erdosproblems.com)
$50
[]
null
null
null
null
null
null
null
null
null
null
30,006,723
EP-106
Erdős Problem #106: Geometry
Draw $n$ squares inside the unit square with no common interior point. Let $f(n)$ be the maximum possible sum of the side-lengths of the squares. Is $f(k^2+1)=k$?
Erdős Problems (#106, https://www.erdosproblems.com/106). Maintainer status: DISPROVED (LEAN).
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/106", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "geometry" ]
null
null
null
null
https://www.erdosproblems.com/106
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,724
EP-107
Erdős Problem #107: Geometry, Convex
Let $f(n)$ be minimal such that any $f(n)$ points in $\mathbb{R}^2$, no three on a line, contain $n$ points which form the vertices of a convex $n$-gon. Prove that $f(n)=2^{n-2}+1$.
Erdős Problems (#107, https://www.erdosproblems.com/107). Maintainer status: FALSIFIABLE. Erdős prize: $500. 'Happy Ending' problem OEIS: A000051. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.107).
3
open
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
[ "GEO-035", "GEOM-020" ]
{ "source_url": "https://www.erdosproblems.com/107", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "falsifiable" }
null
null
null
'Happy Ending' problem
[ "erdos-problems", "geometry", "convex" ]
null
null
null
null
https://www.erdosproblems.com/107
Erdős Problems (erdosproblems.com)
$500
[]
null
null
null
null
null
null
null
null
null
null
30,006,725
EP-109
Erdős Problem #109: Additive Combinatorics
Any $A\subseteq \mathbb{N}$ of positive upper density contains a sumset $B+C$ where both $B$ and $C$ are infinite.
Erdős Problems (#109, https://www.erdosproblems.com/109). Maintainer status: PROVED (LEAN). Erdős sumset conjecture Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.109).
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/109", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
Erdős sumset conjecture
[ "erdos-problems", "additive-combinatorics" ]
null
null
null
null
https://www.erdosproblems.com/109
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,726
EP-110
Erdős Problem #110: Graph Theory, Chromatic Number
Is there some $F(n)$ such that every graph with chromatic number $\aleph_1$ has, for all large $n$, a subgraph with chromatic number $n$ on at most $F(n)$ vertices?
Erdős Problems (#110, https://www.erdosproblems.com/110). Maintainer status: DISPROVED.
3
solved
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/110", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved" }
null
null
null
null
[ "erdos-problems", "graph-theory", "chromatic-number", "cycles" ]
null
null
null
null
https://www.erdosproblems.com/110
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,727
EP-113
Erdős Problem #113: Graph Theory, Turan Number
If $G$ is bipartite then $\mathrm{ex}(n;G)\ll n^{3/2}$ if and only $G$ is $2$-degenerate, that is, $G$ contains no induced subgraph with minimal degree at least 3.
Erdős Problems (#113, https://www.erdosproblems.com/113). Maintainer status: DISPROVED (LEAN). Erdős prize: $500. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.113).
3
solved
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/113", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "graph-theory", "turan-number" ]
null
null
null
null
https://www.erdosproblems.com/113
Erdős Problems (erdosproblems.com)
$500
[]
null
null
null
null
null
null
null
null
null
null
30,006,728
EP-115
Erdős Problem #115: Polynomials, Analysis
If $p(z)$ is a polynomial of degree $n$ such that $\{z: \lvert p(z)\rvert\leq 1\}$ is connected then is it true that\[\max_{\substack{z\in\mathbb{C}\\ \lvert p(z)\rvert\leq 1}} \lvert p'(z)\rvert \leq (\tfrac{1}{2}+o(1))n^2?\]
Erdős Problems (#115, https://www.erdosproblems.com/115). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.115).
3
solved
Paul Erdős
null
8
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 8, "name": "analysis", "display_name": "Analysis", "description": "Limits, continuity, calculus, and function theory.", "slug": "analysis", "order_index": 8, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/115", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "polynomials", "analysis" ]
null
null
null
null
https://www.erdosproblems.com/115
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,729
EP-116
Erdős Problem #116: Polynomials, Analysis
Let $p(z)=\prod_{i=1}^n (z-z_i)$ for $\lvert z_i\rvert \leq 1$. Is it true that\[\lvert\{ z: \lvert p(z)\rvert <1\}\rvert>n^{-O(1)}\](or perhaps even $>(\log n)^{-O(1)}$)?
Erdős Problems (#116, https://www.erdosproblems.com/116). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.116).
3
solved
Paul Erdős
null
8
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 8, "name": "analysis", "display_name": "Analysis", "description": "Limits, continuity, calculus, and function theory.", "slug": "analysis", "order_index": 8, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/116", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "polynomials", "analysis" ]
null
null
null
null
https://www.erdosproblems.com/116
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,730
EP-118
Erdős Problem #118: Set Theory, Ramsey Theory
Let $\alpha$ be a cardinal or ordinal number or an order type such that every two-colouring of $K_\alpha$ contains either a red $K_\alpha$ or a blue $K_3$. For every $n\geq 3$ must every two-colouring of $K_\alpha$ contain either a red $K_\alpha$ or a blue $K_n$?
Erdős Problems (#118, https://www.erdosproblems.com/118). Maintainer status: DISPROVED.
3
solved
Paul Erdős
null
10
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 10, "name": "set_theory", "display_name": "Set Theory", "description": "Foundations of mathematics, infinite sets, and cardinality.", "slug": "set-theory", "order_index": 10, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/118", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved" }
null
null
null
null
[ "erdos-problems", "set-theory", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/118
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,731
EP-121
Erdős Problem #121: Number Theory, Squares
Let $F_{k}(N)$ be the size of the largest $A\subseteq \{1,\ldots,N\}$ such that the product of no $k$ many distinct elements of $A$ is a square. Is $F_5(N)=(1-o(1))N$? More generally, is $F_{2k+1}(N)=(1-o(1))N$?
Erdős Problems (#121, https://www.erdosproblems.com/121). Maintainer status: DISPROVED (LEAN). OEIS: A028391, A013928, A372306, A373319, A373178, A360659, A373114, A143301. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.121).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/121", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "squares" ]
null
null
null
null
https://www.erdosproblems.com/121
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,732
EP-127
Erdős Problem #127: Is there an infinite sequence of $m_i$ such that $f(m_i)\to \infty$?
Let $f(m)$ be maximal such that every graph with $m$ edges must contain a bipartite graph with\[\geq \frac{m}{2}+\frac{\sqrt{8m+1}-1}{8}+f(m)\]edges. Is there an infinite sequence of $m_i$ such that $f(m_i)\to \infty$?
Erdős Problems (#127, https://www.erdosproblems.com/127). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.127).
3
solved
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/127", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "graph-theory" ]
null
null
null
null
https://www.erdosproblems.com/127
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,733
EP-128
Erdős Problem #128: Must $G$ contain a triangle?
Let $G$ be a graph with $n$ vertices such that every induced subgraph on $\geq \lfloor n/2\rfloor$ vertices has more than $n^2/50$ edges. Must $G$ contain a triangle?
Erdős Problems (#128, https://www.erdosproblems.com/128). Maintainer status: FALSIFIABLE. Erdős prize: $250. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.128).
3
open
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/128", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "falsifiable" }
null
null
null
null
[ "erdos-problems", "graph-theory" ]
null
null
null
null
https://www.erdosproblems.com/128
Erdős Problems (erdosproblems.com)
$250
[]
null
null
null
null
null
null
null
null
null
null
30,006,734
EP-133
Erdős Problem #133:
Let $f(n)$ be minimal such that every triangle-free graph $G$ with $n$ vertices and diameter $2$ contains a vertex with degree $\geq f(n)$. What is the order of growth of $f(n)$? Does $f(n)/\sqrt{n}\to \infty$?
Erdős Problems (#133, https://www.erdosproblems.com/133). Maintainer status: DISPROVED. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.133).
3
solved
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/133", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved" }
null
null
null
null
[ "erdos-problems", "graph-theory" ]
null
null
null
null
https://www.erdosproblems.com/133
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,735
EP-134
Erdős Problem #134: Graph Theory
Let $\epsilon,\delta>0$ and $n$ be sufficiently large in terms of $\epsilon$ and $\delta$. Let $G$ be a triangle-free graph on $n$ vertices with maximum degree $<n^{1/2-\epsilon}$. Can $G$ be made into a triangle-free graph with diameter $2$ by adding at most $\delta n^2$ edges?
Erdős Problems (#134, https://www.erdosproblems.com/134). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.134).
3
solved
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/134", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "graph-theory" ]
null
null
null
null
https://www.erdosproblems.com/134
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,736
EP-135
Erdős Problem #135: Must $A$ determine $\gg n^2$ many distances?
Let $A\subset \mathbb{R}^2$ be a set of $n$ points such that any subset of size $4$ determines at least $5$ distinct distances. Must $A$ determine $\gg n^2$ many distances?
Erdős Problems (#135, https://www.erdosproblems.com/135). Maintainer status: DISPROVED (LEAN). Erdős prize: $250.
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/135", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "distances", "geometry" ]
null
null
null
null
https://www.erdosproblems.com/135
Erdős Problems (erdosproblems.com)
$250
[]
null
null
null
null
null
null
null
null
null
null
30,006,737
EP-136
Erdős Problem #136: Determine the size of $f(n)$
Let $f(n)$ be the smallest number of colours required to colour the edges of $K_n$ such that every $K_4$ contains at least 5 colours. Determine the size of $f(n)$.
Erdős Problems (#136, https://www.erdosproblems.com/136). Maintainer status: SOLVED. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.136).
3
solved
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/136", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "solved" }
null
null
null
null
[ "erdos-problems", "graph-theory" ]
null
null
null
null
https://www.erdosproblems.com/136
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,738
EP-139
Erdős Problem #139: Additive Combinatorics, Arithmetic Progressions
Let $r_k(N)$ be the size of the largest subset of $\{1,\ldots,N\}$ which does not contain a non-trivial $k$-term arithmetic progression. Prove that $r_k(N)=o(N)$.
Erdős Problems (#139, https://www.erdosproblems.com/139). Maintainer status: PROVED (LEAN). Erdős prize: $1000. Szemerédi's theorem OEIS: A003002, A003003, A003004, A003005. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.139).
4
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 4, "level": 4, "name": "L4: Expert", "description": "Very challenging problems at the frontier of mathematical research.", "color_class": "text-red-600 bg-red-50 border-red-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/139", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
Szemerédi's theorem
[ "erdos-problems", "additive-combinatorics", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/139
Erdős Problems (erdosproblems.com)
$1000
[]
null
null
null
null
null
null
null
null
null
null
30,006,739
EP-140
Erdős Problem #140: Additive Combinatorics, Arithmetic Progressions
Let $r_3(N)$ be the size of the largest subset of $\{1,\ldots,N\}$ which does not contain a non-trivial $3$-term arithmetic progression. Prove that $r_3(N)\ll N/(\log N)^C$ for every $C>0$.
Erdős Problems (#140, https://www.erdosproblems.com/140). Maintainer status: PROVED (LEAN). Erdős prize: $500. OEIS: A003002.
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/140", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/140
Erdős Problems (erdosproblems.com)
$500
[]
null
null
null
null
null
null
null
null
null
null
30,006,740
EP-144
Erdős Problem #144: Number Theory, Divisors
The density of integers which have two divisors $d_1,d_2$ such that $d_1<d_2<2d_1$ exists and is equal to $1$.
Erdős Problems (#144, https://www.erdosproblems.com/144). Maintainer status: PROVED (LEAN). Erdős prize: $250. OEIS: A005279.
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/144", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "divisors" ]
null
null
null
null
https://www.erdosproblems.com/144
Erdős Problems (erdosproblems.com)
$250
[]
null
null
null
null
null
null
null
null
null
null
30,006,741
EP-147
Erdős Problem #147: Graph Theory, Turan Number
If $H$ is bipartite with minimum degree $r$ then there exists $\epsilon=\epsilon(H)>0$ such that\[\mathrm{ex}(n;H) \gg n^{2-\frac{1}{r-1}+\epsilon}.\]
Erdős Problems (#147, https://www.erdosproblems.com/147). Maintainer status: DISPROVED (LEAN). Erdős prize: $500. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.147).
3
solved
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/147", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "graph-theory", "turan-number" ]
null
null
null
null
https://www.erdosproblems.com/147
Erdős Problems (erdosproblems.com)
$500
[]
null
null
null
null
null
null
null
null
null
null
30,006,742
EP-150
Erdős Problem #150: Graph Theory
A minimal cut of a graph is a minimal set of vertices whose removal disconnects the graph. Let $c(n)$ be the maximum number of minimal cuts a graph on $n$ vertices can have. Does $c(n)^{1/n}\to \alpha$ for some $\alpha <2$?
Erdős Problems (#150, https://www.erdosproblems.com/150). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.150).
3
solved
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/150", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "graph-theory" ]
null
null
null
null
https://www.erdosproblems.com/150
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,743
EP-154
Erdős Problem #154: Sidon Sets
Let $A\subset \{1,\ldots,N\}$ be a Sidon set with $\lvert A\rvert\sim N^{1/2}$. Must $A+A$ be well-distributed over all small moduli? In particular, must about half the elements of $A+A$ be even and half odd?
Erdős Problems (#154, https://www.erdosproblems.com/154). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.154).
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/154", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "sidon-sets" ]
null
null
null
null
https://www.erdosproblems.com/154
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,744
EP-157
Erdős Problem #157: Does there exist an infinite Sidon set which is an asymptotic basis of order 3?
Does there exist an infinite Sidon set which is an asymptotic basis of order 3?
Erdős Problems (#157, https://www.erdosproblems.com/157). Maintainer status: PROVED. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.157).
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/157", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "sidon-sets" ]
null
null
null
null
https://www.erdosproblems.com/157
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,745
EP-163
Erdős Problem #163: Graph Theory, Ramsey Theory
For any $d\geq 1$ if $H$ is a graph such that every subgraph contains a vertex of degree at most $d$ then $R(H)\ll_d n$.
Erdős Problems (#163, https://www.erdosproblems.com/163). Maintainer status: PROVED. Burr-Erdős conjecture Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.163).
3
solved
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/163", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
Burr-Erdős conjecture
[ "erdos-problems", "graph-theory", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/163
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,746
EP-164
Erdős Problem #164: Number Theory, Primitive Sets
A set $A\subset \mathbb{N}$ is primitive if no member of $A$ divides another. Is the sum\[\sum_{n\in A}\frac{1}{n\log n}\]maximised over all primitive sets when $A$ is the set of primes?
Erdős Problems (#164, https://www.erdosproblems.com/164). Maintainer status: PROVED (LEAN). OEIS: A137245. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.164).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/164", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "primitive-sets" ]
null
null
null
null
https://www.erdosproblems.com/164
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,747
EP-166
Erdős Problem #166: Prove that\[R(4,k) \gg \frac{k^3}{(\log k)^{O(1)}}.\]
Prove that\[R(4,k) \gg \frac{k^3}{(\log k)^{O(1)}}.\]
Erdős Problems (#166, https://www.erdosproblems.com/166). Maintainer status: PROVED. Erdős prize: $250. OEIS: A059442. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.166).
3
solved
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/166", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "graph-theory", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/166
Erdős Problems (erdosproblems.com)
$250
[]
null
null
null
null
null
null
null
null
null
null
30,006,748
EP-167
Erdős Problem #167: Graph Theory
If $G$ is a graph with at most $k$ edge disjoint triangles then can $G$ be made triangle-free after removing at most $2k$ edges?
Erdős Problems (#167, https://www.erdosproblems.com/167). Maintainer status: FALSIFIABLE.
3
open
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/167", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "falsifiable" }
null
null
null
null
[ "erdos-problems", "graph-theory" ]
null
null
null
null
https://www.erdosproblems.com/167
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,749
EP-171
Erdős Problem #171: Additive Combinatorics, Combinatorics
Is it true that for every $\epsilon>0$ and integer $t\geq 1$, if $N$ is sufficiently large and $A$ is a subset of $[t]^N$ of size at least $\epsilon t^N$ then $A$ must contain a combinatorial line $P$ (a set $P=\{p_1,\ldots,p_t\}$ where for each coordinate $1\leq j\leq t$ the $j$th coordinate of $p_i$ is either $i$ or ...
Erdős Problems (#171, https://www.erdosproblems.com/171). Maintainer status: PROVED (LEAN). density Hales-Jewett OEIS: A156989. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.171).
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/171", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
density Hales-Jewett
[ "erdos-problems", "additive-combinatorics", "combinatorics" ]
null
null
null
null
https://www.erdosproblems.com/171
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,750
EP-175
Erdős Problem #175: Number Theory, Binomial Coefficients
Show that, for any $n\geq 5$, the binomial coefficient $\binom{2n}{n}$ is not squarefree.
Erdős Problems (#175, https://www.erdosproblems.com/175). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.175).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/175", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "binomial-coefficients" ]
null
null
null
null
https://www.erdosproblems.com/175
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,751
EP-178
Erdős Problem #178: Discrepancy
Let $A_1,A_2,\ldots$ be an infinite collection of infinite sets of integers, say $A_i=\{a_{i1}<a_{i2}<\cdots\}$. Does there exist some $f:\mathbb{N}\to\{-1,1\}$ such that\[\max_{m, 1\leq i\leq d} \left\lvert \sum_{1\leq j\leq m} f(a_{ij})\right\rvert \ll_d 1\]for all $d\geq 1$?
Erdős Problems (#178, https://www.erdosproblems.com/178). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.178).
3
solved
Paul Erdős
null
8
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 8, "name": "analysis", "display_name": "Analysis", "description": "Limits, continuity, calculus, and function theory.", "slug": "analysis", "order_index": 8, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/178", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "discrepancy" ]
null
null
null
null
https://www.erdosproblems.com/178
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,752
EP-179
Erdős Problem #179: Additive Combinatorics, Arithmetic Progressions
Let $1\leq k<\ell$ be integers and define $F_k(N,\ell)$ to be minimal such that every set $A\subset \mathbb{N}$ of size $N$ which contains at least $F_k(N,\ell)$ many $k$-term arithmetic progressions must contain an $\ell$-term arithmetic progression. Find good upper bounds for $F_k(N,\ell)$. Is it true that\[F_3(N,4)=...
Erdős Problems (#179, https://www.erdosproblems.com/179). Maintainer status: PROVED.
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/179", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/179
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,753
EP-182
Erdős Problem #182: Graph Theory
Let $k\geq 3$. What is the maximum number of edges that a graph on $n$ vertices can contain if it does not have a $k$-regular subgraph? Is it $\ll n^{1+o(1)}$?
Erdős Problems (#182, https://www.erdosproblems.com/182). Maintainer status: PROVED.
3
solved
Paul Erdős
null
3
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 3, "name": "graph_theory", "display_name": "Graph Theory", "description": "Problems involving graphs, networks, and their properties.", "slug": "graph-theory", "order_index": 3, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/182", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "graph-theory" ]
null
null
null
null
https://www.erdosproblems.com/182
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,754
EP-185
Erdős Problem #185: 1,2\}^n$ which contains no three points on a line. Is it true that $f_3(n)=o(3^n)$?
Let $f_3(n)$ be the maximal size of a subset of $\{0,1,2\}^n$ which contains no three points on a line. Is it true that $f_3(n)=o(3^n)$?
Erdős Problems (#185, https://www.erdosproblems.com/185). Maintainer status: PROVED (LEAN). OEIS: A003142. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.185).
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/185", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics" ]
null
null
null
null
https://www.erdosproblems.com/185
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,755
EP-186
Erdős Problem #186: Additive Combinatorics
Let $F(N)$ be the maximal size of $A\subseteq \{1,\ldots,N\}$ which is 'non-averaging', so that no $n\in A$ is the arithmetic mean of at least two elements in $A$. What is the order of growth of $F(N)$?
Erdős Problems (#186, https://www.erdosproblems.com/186). Maintainer status: SOLVED. OEIS: A389784.
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/186", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "solved" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics" ]
null
null
null
null
https://www.erdosproblems.com/186
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,756
EP-189
Erdős Problem #189: Geometry, Ramsey Theory
If $\mathbb{R}^2$ is finitely coloured then must there exist some colour class which contains the vertices of a rectangle of every area?
Erdős Problems (#189, https://www.erdosproblems.com/189). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.189).
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/189", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "geometry", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/189
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,757
EP-191
Erdős Problem #191: Combinatorics, Ramsey Theory
Let $C>0$ be arbitrary. Is it true that, if $n$ is sufficiently large depending on $C$, then in any $2$-colouring of $\binom{\{2,\ldots,n\}}{2}$ there exists some $X\subseteq \{2,\ldots,n\}$ such that $\binom{X}{2}$ is monochromatic and\[\sum_{x\in X}\frac{1}{\log x}\geq C?\]
Erdős Problems (#191, https://www.erdosproblems.com/191). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.191).
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/191", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "combinatorics", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/191
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,758
EP-192
Erdős Problem #192: Arithmetic Progressions, Combinatorics
Let $A=\{a_1,a_2,\ldots\}\subset \mathbb{R}^d$ be an infinite sequence such that $a_{i+1}-a_i$ is a positive unit vector (i.e. is of the form $(0,0,\ldots,1,0,\ldots,0)$). For which $d$ must $A$ contain a three-term arithmetic progression?
Erdős Problems (#192, https://www.erdosproblems.com/192). Maintainer status: SOLVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.192).
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/192", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "solved (Lean)" }
null
null
null
null
[ "erdos-problems", "arithmetic-progressions", "combinatorics" ]
null
null
null
null
https://www.erdosproblems.com/192
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,759
EP-194
Erdős Problem #194: Arithmetic Progressions
Let $k\geq 3$. Must any ordering of $\mathbb{R}$ contain a monotone $k$-term arithmetic progression, that is, some $x_1<\cdots<x_k$ which forms an increasing or decreasing $k$-term arithmetic progression?
Erdős Problems (#194, https://www.erdosproblems.com/194). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.194).
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/194", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/194
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,760
EP-198
Erdős Problem #198: Additive Combinatorics, Sidon Sets
If $A\subset \mathbb{N}$ is a Sidon set then must the complement of $A$ contain an infinite arithmetic progression?
Erdős Problems (#198, https://www.erdosproblems.com/198). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.198).
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/198", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics", "sidon-sets", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/198
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,761
EP-199
Erdős Problem #199: Arithmetic Progressions
If $A\subset \mathbb{R}$ does not contain a 3-term arithmetic progression then must $\mathbb{R}\backslash A$ contain an infinite arithmetic progression?
Erdős Problems (#199, https://www.erdosproblems.com/199). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.199).
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/199", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/199
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,762
EP-204
Erdős Problem #204: Covering Systems, Divisors
Are there $n$ such that there is a covering system with moduli the divisors of $n$ which is 'as disjoint as possible'? That is, for all $d\mid n$ with $d>1$ there is an associated $a_d$ such that every integer is congruent to some $a_d\pmod{d}$, and if there is some integer $x$ with\[x\equiv a_d\pmod{d}\textrm{ and }x...
Erdős Problems (#204, https://www.erdosproblems.com/204). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.204).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/204", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "covering-systems", "divisors" ]
null
null
null
null
https://www.erdosproblems.com/204
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,763
EP-205
Erdős Problem #205: Number Theory
Is it true that all sufficiently large $n$ can be written as $2^k+m$ for some $k\geq 0$, where $\Omega(m)<\log\log m$? (Here $\Omega(m)$ is the number of prime divisors of $m$ counted with multiplicity.) What about $<\epsilon \log\log m$? Or some more slowly growing function?
Erdős Problems (#205, https://www.erdosproblems.com/205). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.205).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/205", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/205
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,764
EP-206
Erdős Problem #206: Number Theory, Unit Fractions
Let $x>0$ be a real number. For any $n\geq 1$ let\[R_n(x) = \sum_{i=1}^n\frac{1}{m_i}<x\]be the maximal sum of $n$ distinct unit fractions which is $<x$. Is it true that, for almost all $x$, for sufficiently large $n$, we have\[R_{n+1}(x)=R_n(x)+\frac{1}{m},\]where $m$ is minimal such that $m$ does not appear in $R_n(...
Erdős Problems (#206, https://www.erdosproblems.com/206). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.206).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/206", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/206
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,765
EP-207
Erdős Problem #207: Combinatorics, Hypergraphs
For any $g\geq 2$, if $n$ is sufficiently large and $\equiv 1,3\pmod{6}$ then there exists a 3-uniform hypergraph on $n$ vertices such that - every pair of vertices is contained in exactly one edge (i.e. the graph is a Steiner triple system) and - for any $2\leq j\leq g$ any collection of $j$ edges contains at least ...
Erdős Problems (#207, https://www.erdosproblems.com/207). Maintainer status: PROVED. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.207).
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/207", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "combinatorics", "hypergraphs" ]
null
null
null
null
https://www.erdosproblems.com/207
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,766
EP-209
Erdős Problem #209: Geometry
Let $A$ be a finite collection of $d\geq 4$ non-parallel lines in $\mathbb{R}^2$ such that there are no points where at least four lines from $A$ meet. Must there exist a 'Gallai triangle' (or 'ordinary triangle'): three lines from $A$ which intersect in three points, and each of these intersection points only intersec...
Erdős Problems (#209, https://www.erdosproblems.com/209). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.209).
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/209", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "geometry" ]
null
null
null
null
https://www.erdosproblems.com/209
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,767
EP-210
Erdős Problem #210: Geometry
Let $f(n)$ be minimal such that the following holds. For any $n$ points in $\mathbb{R}^2$, not all on a line, there must be at least $f(n)$ many lines which contain exactly 2 points (called 'ordinary lines'). Does $f(n)\to \infty$? How fast?
Erdős Problems (#210, https://www.erdosproblems.com/210). Maintainer status: PROVED. OEIS: A003034. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.210).
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/210", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "geometry" ]
null
null
null
null
https://www.erdosproblems.com/210
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,768
EP-211
Erdős Problem #211: Geometry
Let $1\leq k<n$. Given $n$ points in $\mathbb{R}^2$, at most $n-k$ on any line, there are $\gg kn$ many lines which contain at least two points.
Erdős Problems (#211, https://www.erdosproblems.com/211). Maintainer status: PROVED. Erdős prize: $100.
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/211", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "geometry" ]
null
null
null
null
https://www.erdosproblems.com/211
Erdős Problems (erdosproblems.com)
$100
[]
null
null
null
null
null
null
null
null
null
null
30,006,769
EP-214
Erdős Problem #214: Must the complement of $S$ contain four points which form a unit square?
Let $S\subset \mathbb{R}^2$ be such that no two points in $S$ are distance $1$ apart. Must the complement of $S$ contain four points which form a unit square?
Erdős Problems (#214, https://www.erdosproblems.com/214). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.214).
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/214", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "geometry", "distances", "ramsey-theory" ]
null
null
null
null
https://www.erdosproblems.com/214
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,770
EP-215
Erdős Problem #215: Geometry
Does there exist $S\subseteq \mathbb{R}^2$ such that every set congruent to $S$ (that is, $S$ after some translation and rotation) contains exactly one point from $\mathbb{Z}^2$?
Erdős Problems (#215, https://www.erdosproblems.com/215). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.215).
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/215", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "geometry" ]
null
null
null
null
https://www.erdosproblems.com/215
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,771
EP-216
Erdős Problem #216: e. with no point in the interior). Does $g(k)$ exist? If so, estimate $g(k)$
Let $g(k)$ be the smallest integer (if any such exists) such that any $g(k)$ points in $\mathbb{R}^2$ contains an empty convex $k$-gon (i.e. with no point in the interior). Does $g(k)$ exist? If so, estimate $g(k)$.
Erdős Problems (#216, https://www.erdosproblems.com/216). Maintainer status: DISPROVED. OEIS: A381776.
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/216", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved" }
null
null
null
null
[ "erdos-problems", "geometry", "convex" ]
null
null
null
null
https://www.erdosproblems.com/216
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,772
EP-219
Erdős Problem #219: Are there arbitrarily long arithmetic progressions of primes?
Are there arbitrarily long arithmetic progressions of primes?
Erdős Problems (#219, https://www.erdosproblems.com/219). Maintainer status: PROVED (LEAN). Green-Tao theorem OEIS: A005115, A113827, A123556. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.219).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/219", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
Green-Tao theorem
[ "erdos-problems", "number-theory", "additive-combinatorics", "primes", "arithmetic-progressions" ]
null
null
null
null
https://www.erdosproblems.com/219
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,773
EP-220
Erdős Problem #220: Number Theory
Let $n\geq 1$ and\[A=\{a_1<\cdots <a_{\phi(n)}\}=\{ 1\leq m<n: (m,n)=1\}.\]Is it true that\[ \sum_{1\leq k<\phi(n)}(a_{k+1}-a_k)^2 \ll \frac{n^2}{\phi(n)}?\]
Erdős Problems (#220, https://www.erdosproblems.com/220). Maintainer status: PROVED (LEAN). Erdős prize: $500. OEIS: A322144. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.220).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/220", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/220
Erdős Problems (erdosproblems.com)
$500
[]
null
null
null
null
null
null
null
null
null
null
30,006,774
EP-221
Erdős Problem #221: Number Theory, Additive Basis
Is there a set $A\subset\mathbb{N}$ such that, for all large $N$,\[\lvert A\cap\{1,\ldots,N\}\rvert \ll N/\log N\]and such that every large integer can be written as $2^k+a$ for some $k\geq 0$ and $a\in A$?
Erdős Problems (#221, https://www.erdosproblems.com/221). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.221).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/221", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "additive-basis" ]
null
null
null
null
https://www.erdosproblems.com/221
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,775
EP-223
Erdős Problem #223: Geometry, Distances
Let $d\geq 2$ and $n\geq 2$. Let $f_d(n)$ be maximal such that there exists some set of $n$ points $A\subseteq \mathbb{R}^d$, with diameter $1$, in which the distance 1 occurs between $f_d(n)$ many pairs of points in $A$. Estimate $f_d(n)$.
Erdős Problems (#223, https://www.erdosproblems.com/223). Maintainer status: SOLVED. OEIS: A008811.
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/223", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "solved" }
null
null
null
null
[ "erdos-problems", "geometry", "distances" ]
null
null
null
null
https://www.erdosproblems.com/223
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,776
EP-224
Erdős Problem #224: Geometry
If $A\subseteq \mathbb{R}^d$ is any set of $2^d+1$ points then some three points in $A$ determine an obtuse angle.
Erdős Problems (#224, https://www.erdosproblems.com/224). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.224).
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/224", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "geometry" ]
null
null
null
null
https://www.erdosproblems.com/224
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,777
EP-225
Erdős Problem #225: Analysis
Let\[ f(\theta) = \sum_{0\leq k\leq n}c_k e^{ik\theta}\]be a trigonometric polynomial all of whose roots are real, such that $\max_{\theta\in [0,2\pi]}\lvert f(\theta)\rvert=1$. Then\[\int_0^{2\pi}\lvert f(\theta)\rvert \mathrm{d}\theta \leq 4.\]
Erdős Problems (#225, https://www.erdosproblems.com/225). Maintainer status: PROVED. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.225).
3
solved
Paul Erdős
null
8
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 8, "name": "analysis", "display_name": "Analysis", "description": "Limits, continuity, calculus, and function theory.", "slug": "analysis", "order_index": 8, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/225", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "analysis" ]
null
null
null
null
https://www.erdosproblems.com/225
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,778
EP-226
Erdős Problem #226: Analysis
Is there an entire non-linear function $f$ such that, for all $x\in\mathbb{R}$, $x$ is rational if and only if $f(x)$ is?
Erdős Problems (#226, https://www.erdosproblems.com/226). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.226).
3
solved
Paul Erdős
null
8
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 8, "name": "analysis", "display_name": "Analysis", "description": "Limits, continuity, calculus, and function theory.", "slug": "analysis", "order_index": 8, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/226", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "analysis" ]
null
null
null
null
https://www.erdosproblems.com/226
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,779
EP-227
Erdős Problem #227: Analysis
Let $f=\sum_{n=0}^\infty a_nz^n$ be an entire function which is not a polynomial. Is it true that if\[\lim_{r\to \infty} \frac{\max_n\lvert a_nr^n\rvert}{\max_{\lvert z\rvert=r}\lvert f(z)\rvert}\]exists then it must be $0$?
Erdős Problems (#227, https://www.erdosproblems.com/227). Maintainer status: DISPROVED.
3
solved
Paul Erdős
null
8
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 8, "name": "analysis", "display_name": "Analysis", "description": "Limits, continuity, calculus, and function theory.", "slug": "analysis", "order_index": 8, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/227", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved" }
null
null
null
null
[ "erdos-problems", "analysis" ]
null
null
null
null
https://www.erdosproblems.com/227
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,780
EP-228
Erdős Problem #228: Analysis, Polynomials
Does there exist, for all large $n$, a polynomial $P$ of degree $n$, with coefficients $\pm 1$, such that\[\sqrt{n} \ll \lvert P(z) \rvert \ll \sqrt{n}\]for all $\lvert z\rvert =1$, with the implied constants independent of $z$ and $n$?
Erdős Problems (#228, https://www.erdosproblems.com/228). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.228).
3
solved
Paul Erdős
null
8
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 8, "name": "analysis", "display_name": "Analysis", "description": "Limits, continuity, calculus, and function theory.", "slug": "analysis", "order_index": 8, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/228", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "analysis", "polynomials" ]
null
null
null
null
https://www.erdosproblems.com/228
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,781
EP-229
Erdős Problem #229: Analysis, Iterated Functions
Let $(S_n)_{n\geq 1}$ be a sequence of sets of complex numbers, none of which have a finite limit point. Does there exist an entire transcendental function $f(z)$ such that, for all $n\geq 1$, there exists some $k_n\geq 0$ such that\[f^{(k_n)}(z) = 0\textrm{ for all }z\in S_n?\]
Erdős Problems (#229, https://www.erdosproblems.com/229). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.229).
3
solved
Paul Erdős
null
8
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 8, "name": "analysis", "display_name": "Analysis", "description": "Limits, continuity, calculus, and function theory.", "slug": "analysis", "order_index": 8, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/229", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "analysis", "iterated-functions" ]
null
null
null
null
https://www.erdosproblems.com/229
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,782
EP-230
Erdős Problem #230: Analysis, Polynomials
Let $P(z)=\sum_{1\leq k\leq n}a_kz^k$ for some $a_k\in \mathbb{C}$ with $\lvert a_k\rvert=1$ for $1\leq k\leq n$. Does there exist a constant $c>0$ such that, for $n\geq 2$, we have\[\max_{\lvert z\rvert=1}\lvert P(z)\rvert \geq (1+c)\sqrt{n}?\]
Erdős Problems (#230, https://www.erdosproblems.com/230). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.230).
3
solved
Paul Erdős
null
8
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 8, "name": "analysis", "display_name": "Analysis", "description": "Limits, continuity, calculus, and function theory.", "slug": "analysis", "order_index": 8, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/230", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "analysis", "polynomials" ]
null
null
null
null
https://www.erdosproblems.com/230
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,783
EP-231
Erdős Problem #231: Combinatorics
Let $S$ be a string of length $2^k-1$ formed from an alphabet of $k$ characters. Must $S$ contain an abelian square: two consecutive blocks $x$ and $y$ such that $y$ is a permutation of $x$?
Erdős Problems (#231, https://www.erdosproblems.com/231). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.231).
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/231", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "combinatorics" ]
null
null
null
null
https://www.erdosproblems.com/231
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,784
EP-232
Erdős Problem #232: Geometry, Distances
For $A\subset \mathbb{R}^2$ we define the upper density as\[\overline{\delta}(A)=\limsup_{R\to \infty}\frac{\lambda(A \cap B_R)}{\lambda(B_R)},\]where $\lambda$ is the Lebesgue measure and $B_R$ is the ball of radius $R$. Estimate\[m_1=\sup \overline{\delta}(A),\]where $A$ ranges over all measurable subsets of $\mathb...
Erdős Problems (#232, https://www.erdosproblems.com/232). Maintainer status: PROVED.
3
solved
Paul Erdős
null
6
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 6, "name": "geometry", "display_name": "Geometry", "description": "Euclidean and non-Euclidean geometry, geometric structures.", "slug": "geometry", "order_index": 6, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/232", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "geometry", "distances" ]
null
null
null
null
https://www.erdosproblems.com/232
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,785
EP-235
Erdős Problem #235: Number Theory
Let $N_k=2\cdot 3\cdots p_k$ and $\{a_1<a_2<\cdots <a_{\phi(N_k)}\}$ be the integers $<N_k$ which are relatively prime to $N_k$. Then, for any $c\geq 0$, the limit\[\frac{\#\{ a_i-a_{i-1}\leq c \frac{N_k}{\phi(N_k)}: 2\leq i\leq \phi(N_k)\}}{\phi(N_k)}\]exists and is a continuous function of $c$.
Erdős Problems (#235, https://www.erdosproblems.com/235). Maintainer status: PROVED. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.235).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/235", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/235
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,786
EP-237
Erdős Problem #237: Number Theory, Primes
Let $A\subseteq \mathbb{N}$ be a set such that $\lvert A\cap \{1,\ldots,N\}\rvert \gg \log N$ for all large $N$. Let $f(n)$ count the number of solutions to $n=p+a$ for $p$ prime and $a\in A$. Is it true that $\limsup f(n)=\infty$?
Erdős Problems (#237, https://www.erdosproblems.com/237). Maintainer status: PROVED (LEAN).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/237", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "primes" ]
null
null
null
null
https://www.erdosproblems.com/237
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,787
EP-239
Erdős Problem #239: Is it true that\[ \lim_{N\to \infty}\frac{1}{N}\sum_{n\leq N}f(n)\]always exists?
Let $f:\mathbb{N}\to \{-1,1\}$ be a multiplicative function. Is it true that\[ \lim_{N\to \infty}\frac{1}{N}\sum_{n\leq N}f(n)\]always exists?
Erdős Problems (#239, https://www.erdosproblems.com/239). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.239).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/239", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/239
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,788
EP-240
Erdős Problem #240: Number Theory, Primes
Is there an infinite set of primes $P$ such that if $\{a_1<a_2<\cdots\}$ is the set of integers divisible only by primes in $P$ then $\lim a_{i+1}-a_i=\infty$?
Erdős Problems (#240, https://www.erdosproblems.com/240). Maintainer status: PROVED.
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/240", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "number-theory", "primes" ]
null
null
null
null
https://www.erdosproblems.com/240
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,789
EP-242
Erdős Problem #242: Number Theory, Unit Fractions
For every $n>2$ there exist distinct integers $1\leq x<y<z$ such that\[\frac{4}{n} = \frac{1}{x}+\frac{1}{y}+\frac{1}{z}.\]
Erdős Problems (#242, https://www.erdosproblems.com/242). Maintainer status: FALSIFIABLE. Erdős-Straus conjecture OEIS: A073101, A075245, A075246, A075247, A075248, A287116. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.242).
3
open
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
[ "NT-012", "NT-024", "OPG-37397" ]
{ "source_url": "https://www.erdosproblems.com/242", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "falsifiable" }
null
null
null
Erdős-Straus conjecture
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/242
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,790
EP-245
Erdős Problem #245: Additive Combinatorics
Let $A\subseteq \mathbb{N}$ be an infinite set such that $\lvert A\cap \{1,\ldots,N\}\rvert=o(N)$. Is it true that\[\limsup_{N\to \infty}\frac{\lvert (A+A)\cap \{1,\ldots,N\}\rvert}{\lvert A\cap \{1,\ldots,N\}\rvert}\geq 3?\]
Erdős Problems (#245, https://www.erdosproblems.com/245). Maintainer status: PROVED. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.245).
3
solved
Paul Erdős
null
2
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 2, "name": "combinatorics", "display_name": "Combinatorics", "description": "Counting problems, graph theory, discrete structures.", "slug": "combinatorics", "order_index": 2, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/245", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "additive-combinatorics" ]
null
null
null
null
https://www.erdosproblems.com/245
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,791
EP-246
Erdős Problem #246: Number Theory
Let $(a,b)=1$. The set $\{a^kb^l: k,l\geq 0\}$ is complete - that is, every large integer is the sum of distinct integers of the form $a^kb^l$ with $k,l\geq 0$.
Erdős Problems (#246, https://www.erdosproblems.com/246). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.246).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/246", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/246
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,792
EP-248
Erdős Problem #248: Number Theory
Are there infinitely many $n$ such that, for all $k\geq 1$,\[ \omega(n+k) \ll k?\](Here $\omega(n)$ is the number of distinct prime divisors of $n$.)
Erdős Problems (#248, https://www.erdosproblems.com/248). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.248).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/248", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/248
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,793
EP-250
Erdős Problem #250: Number Theory, Irrationality
Is\[\sum \frac{\sigma(n)}{2^n}\]irrational? (Here $\sigma(n)$ is the sum of divisors function.)
Erdős Problems (#250, https://www.erdosproblems.com/250). Maintainer status: PROVED (LEAN). OEIS: A066766. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.250).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/250", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/250
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,794
EP-253
Erdős Problem #253: Number Theory
Let $1\leq a_1<a_2<\cdots $ be an infinite sequence of integers such that $a_{i+1}/a_i\to 1$. If every infinite arithmetic progression contains infinitely many integers which are the sum of distinct $a_i$ then every sufficiently large integer is the sum of distinct $a_i$.
Erdős Problems (#253, https://www.erdosproblems.com/253). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.253).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/253", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/253
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,795
EP-255
Erdős Problem #255: Discrepancy
Let $z_1,z_2,\ldots \in [0,1]$ be an infinite sequence, and define the discrepancy\[D_N(I) = \#\{ n\leq N: z_n\in I\} - N\lvert I\rvert.\]Must there exist some interval $I\subseteq [0,1]$ such that\[\limsup_{N\to \infty}\lvert D_N(I)\rvert =\infty?\]
Erdős Problems (#255, https://www.erdosproblems.com/255). Maintainer status: PROVED (LEAN).
3
solved
Paul Erdős
null
8
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 8, "name": "analysis", "display_name": "Analysis", "description": "Limits, continuity, calculus, and function theory.", "slug": "analysis", "order_index": 8, "created_at": "2026-07-31T15:26:25.671Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/255", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "discrepancy" ]
null
null
null
null
https://www.erdosproblems.com/255
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,796
EP-259
Erdős Problem #259: Is the sum\[\sum_{n} \mu(n)^2\frac{n}{2^n}\]irrational?
Is the sum\[\sum_{n} \mu(n)^2\frac{n}{2^n}\]irrational?
Erdős Problems (#259, https://www.erdosproblems.com/259). Maintainer status: PROVED (LEAN). OEIS: A371134. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.259).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/259", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/259
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,797
EP-262
Erdős Problem #262: Irrationality
Suppose $a_1<a_2<\cdots$ is a sequence of integers such that for all integer sequences $t_n$ with $t_n\geq 1$ the sum\[\sum_{n=1}^\infty \frac{1}{t_na_n}\]is irrational. How slowly can $a_n$ grow?
Erdős Problems (#262, https://www.erdosproblems.com/262). Maintainer status: SOLVED (LEAN).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/262", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "solved (Lean)" }
null
null
null
null
[ "erdos-problems", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/262
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,798
EP-266
Erdős Problem #266: There exists some integer $t\geq 1$ such that\[\sum \frac{1}{a_n+t}\]is irrational
Let $a_n$ be an infinite sequence of positive integers such that $\sum \frac{1}{a_n}$ converges. There exists some integer $t\geq 1$ such that\[\sum \frac{1}{a_n+t}\]is irrational.
Erdős Problems (#266, https://www.erdosproblems.com/266). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.266).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/266", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/266
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,799
EP-268
Erdős Problem #268: Number Theory
Let $X\subseteq \mathbb{R}^3$ be the set of all points of the shape\[\left( \sum_{n\in A} \frac{1}{n},\sum_{n\in A}\frac{1}{n+1},\sum_{n\in A} \frac{1}{n+2}\right) \]as $A\subseteq\mathbb{N}$ ranges over all infinite sets with $\sum_{n\in A}\frac{1}{n}<\infty$. Does $X$ contain an open set?
Erdős Problems (#268, https://www.erdosproblems.com/268). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.268).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/268", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory" ]
null
null
null
null
https://www.erdosproblems.com/268
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,800
EP-270
Erdős Problem #270: Irrationality
Let $f(n)\to \infty$ as $n\to \infty$. Is it true that\[\sum_{n\geq 1} \frac{1}{(n+1)\cdots (n+f(n))}\]is irrational?
Erdős Problems (#270, https://www.erdosproblems.com/270). Maintainer status: DISPROVED (LEAN). OEIS: A073016. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.270).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/270", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "irrationality" ]
null
null
null
null
https://www.erdosproblems.com/270
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,801
EP-275
Erdős Problem #275: Number Theory, Covering Systems
If a finite system of $r$ congruences $\{ a_i\pmod{n_i}: 1\leq i\leq r\}$ (the $n_i$ are not necessarily distinct) covers $2^r$ consecutive integers then it covers all integers.
Erdős Problems (#275, https://www.erdosproblems.com/275). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.275).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/275", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "covering-systems" ]
null
null
null
null
https://www.erdosproblems.com/275
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,802
EP-277
Erdős Problem #277: Number Theory, Covering Systems
Is it true that, for every $c$, there exists an $n$ such that $\sigma(n)>cn$ but there is no covering system whose moduli all distinct divisors of $n$ (which are $>1$)?
Erdős Problems (#277, https://www.erdosproblems.com/277). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.277).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/277", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "covering-systems" ]
null
null
null
null
https://www.erdosproblems.com/277
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,803
EP-280
Erdős Problem #280: Number Theory, Covering Systems
Let $n_1<n_2<\cdots $ be an infinite sequence of integers with associated $a_k\pmod{n_k}$, such that for some $\epsilon>0$ we have $n_k>(1+\epsilon)k\log k$ for all $k$. Then\[\#\{ m<n_k: m\not\equiv a_i\pmod{n_i} \textrm{ for }1\leq i\leq k\}\neq o(k).\]
Erdős Problems (#280, https://www.erdosproblems.com/280). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.280).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/280", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "covering-systems" ]
null
null
null
null
https://www.erdosproblems.com/280
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,804
EP-284
Erdős Problem #284: \]Is it true that\[f(k)=(1+o(1))\frac{k}{e-1}?\]
Let $f(k)$ be the maximal value of $n_1$ such that there exist $n_1<n_2<\cdots <n_k$ with\[1=\frac{1}{n_1}+\cdots+\frac{1}{n_k}.\]Is it true that\[f(k)=(1+o(1))\frac{k}{e-1}?\]
Erdős Problems (#284, https://www.erdosproblems.com/284). Maintainer status: PROVED.
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/284", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/284
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,805
EP-285
Erdős Problem #285: \]Is it true that\[f(k)=(1+o(1))\frac{e}{e-1}k?\]
Let $f(k)$ be the minimal value of $n_k$ such that there exist $n_1<n_2<\cdots <n_k$ with\[1=\frac{1}{n_1}+\cdots+\frac{1}{n_k}.\]Is it true that\[f(k)=(1+o(1))\frac{e}{e-1}k?\]
Erdős Problems (#285, https://www.erdosproblems.com/285). Maintainer status: PROVED (LEAN). OEIS: A030659. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.285).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/285", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/285
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,806
EP-286
Erdős Problem #286: Number Theory, Unit Fractions
Let $k\geq 2$. Is it true that there exists an interval $I$ of width $(e-1+o(1))k$ and integers $n_1<\cdots<n_k\in I$ such that\[1=\frac{1}{n_1}+\cdots+\frac{1}{n_k}?\]
Erdős Problems (#286, https://www.erdosproblems.com/286). Maintainer status: PROVED. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.286).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/286", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/286
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,807
EP-287
Erdős Problem #287: Number Theory, Unit Fractions
Let $k\geq 2$. Is it true that, for any distinct integers $1<n_1<\cdots <n_k$ such that\[1=\frac{1}{n_1}+\cdots+\frac{1}{n_k}\]we must have $\max(n_{i+1}-n_i)\geq 3$?
Erdős Problems (#287, https://www.erdosproblems.com/287). Maintainer status: FALSIFIABLE. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.287).
3
open
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/287", "checked_at": "2026-10-16", "kind": "open", "evidence": "maintained_source", "maintainer_status": "falsifiable" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/287
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,808
EP-290
Erdős Problem #290: Number Theory, Unit Fractions
Let $a\geq 1$. Must there exist some $b>a$ such that\[\sum_{a\leq n\leq b}\frac{1}{n}=\frac{r_1}{s_1}\textrm{ and }\sum_{a\leq n\leq b+1}\frac{1}{n}=\frac{r_2}{s_2},\]with $(r_i,s_i)=1$ and $s_2<s_1$? If so, how does this $b(a)$ grow with $a$?
Erdős Problems (#290, https://www.erdosproblems.com/290). Maintainer status: PROVED (LEAN). OEIS: A375081. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.290).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/290", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/290
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,809
EP-292
Erdős Problem #292: Explore $A$. In particular, does $A$ have density $1$?
Let $A$ be the set of $n\in \mathbb{N}$ such that there exist $1\leq m_1<\cdots <m_k=n$ with $\sum\tfrac{1}{m_i}=1$. Explore $A$. In particular, does $A$ have density $1$?
Erdős Problems (#292, https://www.erdosproblems.com/292). Maintainer status: PROVED. OEIS: A092671. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.292).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/292", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/292
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,810
EP-294
Erdős Problem #294: Number Theory, Unit Fractions
Let $N\geq 1$ and let $t(N)$ be the least integer $t$ such that there is no solution to\[1=\frac{1}{n_1}+\cdots+\frac{1}{n_k}\]with $t=n_1<\cdots <n_k\leq N$. Estimate $t(N)$.
Erdős Problems (#294, https://www.erdosproblems.com/294). Maintainer status: PROVED.
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/294", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/294
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,811
EP-296
Erdős Problem #296: Number Theory, Unit Fractions
Let $N\geq 1$ and let $k(N)$ be maximal such that there are $k$ disjoint $A_1,\ldots,A_k\subseteq \{1,\ldots,N\}$ with $\sum_{n\in A_i}\frac{1}{n}=1$ for all $i$. Estimate $k(N)$. Is it true that $k(N)=o(\log N)$?
Erdős Problems (#296, https://www.erdosproblems.com/296). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.296).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/296", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/296
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,812
EP-297
Erdős Problem #297: Number Theory, Unit Fractions
Let $N\geq 1$. How many $A\subseteq \{1,\ldots,N\}$ are there such that $\sum_{n\in A}\frac{1}{n}=1$?
Erdős Problems (#297, https://www.erdosproblems.com/297). Maintainer status: SOLVED. OEIS: A092670.
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/297", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "solved" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/297
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,813
EP-298
Erdős Problem #298: Number Theory, Unit Fractions
Does every set $A\subseteq \mathbb{N}$ of positive density contain some finite $S\subset A$ such that $\sum_{n\in S}\frac{1}{n}=1$?
Erdős Problems (#298, https://www.erdosproblems.com/298). Maintainer status: PROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.298).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/298", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "proved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/298
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,814
EP-299
Erdős Problem #299: Number Theory, Unit Fractions
Is there an infinite sequence $a_1<a_2<\cdots $ such that $a_{i+1}-a_i=O(1)$ and no finite sum of $\frac{1}{a_i}$ is equal to $1$?
Erdős Problems (#299, https://www.erdosproblems.com/299). Maintainer status: DISPROVED (LEAN). Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.299).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/299", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "disproved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/299
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null
30,006,815
EP-300
Erdős Problem #300: Number Theory, Unit Fractions
Let $A(N)$ denote the maximal cardinality of $A\subseteq \{1,\ldots,N\}$ such that $\sum_{n\in S}\frac{1}{n}\neq 1$ for all $S\subseteq A$. Estimate $A(N)$.
Erdős Problems (#300, https://www.erdosproblems.com/300). Maintainer status: SOLVED (LEAN). OEIS: A390393. Formalized in Lean (google-deepmind/formal-conjectures, ErdosProblems.300).
3
solved
Paul Erdős
null
1
8
0
0
2026-10-16T14:00:00
2026-10-16T14:00:00
true
{ "id": 1, "name": "number_theory", "display_name": "Number Theory", "description": "Properties of integers, prime numbers, Diophantine equations.", "slug": "number-theory", "order_index": 1, "created_at": "2026-07-31T15:26:25.670Z" }
{ "id": 3, "level": 3, "name": "L3: Advanced", "description": "Difficult problems requiring specialized knowledge and sophisticated techniques.", "color_class": "text-yellow-600 bg-yellow-50 border-yellow-200" }
{ "id": 8, "name": "erdos_problems", "display_name": "Erdős Problems", "description": "A collection of open problems posed by Paul Erdős, one of the most prolific mathematicians of the 20th century. These problems span combinatorics, number theory, graph theory, and analysis.", "slug": "erdos-problems", "or...
null
{ "source_url": "https://www.erdosproblems.com/300", "checked_at": "2026-10-16", "kind": "resolution", "evidence": "maintained_source", "maintainer_status": "solved (Lean)" }
null
null
null
null
[ "erdos-problems", "number-theory", "unit-fractions" ]
null
null
null
null
https://www.erdosproblems.com/300
Erdős Problems (erdosproblems.com)
null
[]
null
null
null
null
null
null
null
null
null
null