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import OAI.Combinatorics.CycleDecomposition.BatchRouting
namespace OAI
universe cycleUniverse1 cycleUniverse2 cycleUniverse3 cycleUniverse4 cycleUniverse5 cycleUniverse6 cycleUniverse7 cycleUniverse8 cycleUniverse9 cycleUniverse10 cycleUniverse11 cycleUniverse12 cycleUniverse13 cycleUniverse14 cycleUniverse15 cycleUniverse16 cycleUniverse17 cycleUniverse18 cycleUniverse19 cycleUniverse20
section
open Filter Asymptotics Real
open scoped Topology
noncomputable section
open MeasureTheory ProbabilityTheory Finset
section
namespace ErdosGallai.Batch
noncomputable section
open Real Filter Asymptotics
lemma routing_length_upper (r h : ℝ) (hr : 2 ≤ r) (hh : 0 < h) (hhr : h ≤ r) :
(routingLength r h : ℝ) ≤ 108*(r/h)*(logb 2 r)^2 := by
have hr0 : 0 < r := by linarith
have hl : 1 ≤ logb 2 r := by
simpa using Real.logb_le_logb_of_le (by norm_num : (1:ℝ) < 2)
(by norm_num : (0:ℝ) < 2) hr
have hR : 1 ≤ r/h := (le_div_iff₀ hh).mpr (by simpa using hhr)
have hlog : logb 2 (2*r) = 1 + logb 2 r := by
rw [Real.logb_mul (by norm_num) hr0.ne']
norm_num
have hg := Nat.ceil_lt_add_one (show 0 ≤ 8*(r/h)*logb 2 (2*r) by rw [hlog]; positivity)
have hd := Nat.ceil_lt_add_one (show 0 ≤ logb 2 r by linarith)
change (routingG r h : ℝ) < 8*(r/h)*logb 2 (2*r)+1 at hg
change (routingDepth r : ℝ) < logb 2 r + 1 at hd
rw [hlog] at hg
have hprod : 1 ≤ (r/h)*logb 2 r := by
nlinarith [mul_nonneg (sub_nonneg.mpr hR) (sub_nonneg.mpr hl)]
have hg' : (routingG r h : ℝ) ≤ 18*(r/h)*logb 2 r := by nlinarith
have hd' : (1 + routingDepth r : ℝ) ≤ 3*logb 2 r := by linarith
have hm := mul_le_mul hg' hd' (by positivity) (by positivity)
dsimp [routingLength]
push_cast
nlinarith
lemma eventually_logb_le_power (ε : ℝ) (hε : 0 < ε) :
∀ᶠ D : ℝ in atTop, logb 2 D ≤ D^ε := by
have ho := (isLittleO_log_rpow_atTop hε).const_mul_left (1 / log 2)
filter_upwards [ho.eventuallyLE, eventually_ge_atTop (1:ℝ)] with D hD h1
simpa [Real.logb, div_eq_mul_inv, mul_comm, Real.norm_eq_abs,
abs_of_nonneg (Real.log_nonneg h1), abs_of_nonneg (Real.rpow_nonneg (by linarith) ε),
abs_of_pos (show 0 < (log 2)⁻¹ by positivity),
abs_of_pos (Real.log_pos (by norm_num : (1:ℝ) < 2))] using hD
lemma eventually_constant_le_power (C ε : ℝ) (hε : 0 < ε) :
∀ᶠ D : ℝ in atTop, C ≤ D^ε :=
(tendsto_rpow_atTop hε).eventually (eventually_ge_atTop C)
lemma eventually_const_mul_power_le (C α β : ℝ) (hab : α < β) :
∀ᶠ D : ℝ in atTop, C*D^α ≤ D^β := by
filter_upwards [eventually_constant_le_power C (β-α) (by linarith),
eventually_gt_atTop (0:ℝ)] with D hc hD
calc
C*D^α ≤ D^(β-α)*D^α := mul_le_mul_of_nonneg_right hc (Real.rpow_nonneg hD.le _)
_ = D^β := by rw [← Real.rpow_add hD]; congr 1; ring
theorem eventually_routing_length (c β γ δ : ℝ) (hc : 0 < c) (hβ : 0 < β)
(hδ : 0 < δ) :
∀ᶠ D : ℝ in atTop, ∀ r : ℝ, 2 ≤ r → r ≤ D^β → c*D^γ ≤ r →
(routingLength r (c*D^γ) : ℝ) ≤ D^(β-γ+δ) := by
filter_upwards [eventually_logb_le_power (δ/4) (by positivity),
eventually_constant_le_power (108*β^2/c) (δ/2) (by positivity),
eventually_gt_atTop (1:ℝ)] with D hlog hconst hD r hr hrD hhr
have hD0 : 0 < D := by linarith
have hpowγ : 0 < D^γ := Real.rpow_pos_of_pos hD0 _
have hden : 0 < c*D^γ := mul_pos hc hpowγ
have hlog0 : 0 ≤ logb 2 r := (Real.logb_pos (by norm_num) (by linarith)).le
have hlogR : logb 2 r ≤ β*D^(δ/4) := by
have hh := Real.logb_le_logb_of_le (by norm_num : (1:ℝ) < 2)
(by linarith : 0 < r) hrD
rw [Real.logb_rpow_eq_mul_logb_of_pos hD0] at hh
exact hh.trans (mul_le_mul_of_nonneg_left hlog hβ.le)
have hratio : r/(c*D^γ) ≤ D^(β-γ)/c := by
calc
_ ≤ D^β/(c*D^γ) := div_le_div_of_nonneg_right hrD hden.le
_ = _ := by rw [Real.rpow_sub hD0]; ring
have hsq : (logb 2 r)^2 ≤ β^2*D^(δ/2) := by
calc
_ ≤ (β*D^(δ/4))^2 := pow_le_pow_left₀ hlog0 hlogR 2
_ = _ := by rw [mul_pow, ← Real.rpow_mul_natCast hD0.le]; congr 2; ring
calc
(routingLength r (c*D^γ) : ℝ) ≤ 108*(r/(c*D^γ))*(logb 2 r)^2 :=
routing_length_upper r (c*D^γ) hr hden hhr
_ ≤ 108*(D^(β-γ)/c)*(β^2*D^(δ/2)) := by gcongr
_ = (108*β^2/c)*D^(β-γ+δ/2) := by rw [Real.rpow_add hD0]; ring
_ ≤ D^(δ/2)*D^(β-γ+δ/2) :=
mul_le_mul_of_nonneg_right hconst (Real.rpow_nonneg hD0.le _)
_ = D^(β-γ+δ) := by rw [← Real.rpow_add hD0]; congr 1; ring
theorem batch_routing_margin : ∃ D₀ : ℝ, 1 < D₀ ∧ ∀ D ≥ D₀,
∀ r : ℝ, D^(9/10:ℝ) ≤ r → r ≤ D^(51/50:ℝ) →
2 ≤ r ∧ 64*((routingLength r (D^(9/10:ℝ)/4) : ℝ)^2*
(D^(1/100:ℝ)+D^(3/10:ℝ))+2*D^(3/10:ℝ)) ≤ D^(9/10:ℝ)/4 := by
have hev : ∀ᶠ D : ℝ in atTop, ∀ r : ℝ, D^(9/10:ℝ) ≤ r → r ≤ D^(51/50:ℝ) →
2 ≤ r ∧ 64*((routingLength r (D^(9/10:ℝ)/4) : ℝ)^2*
(D^(1/100:ℝ)+D^(3/10:ℝ))+2*D^(3/10:ℝ)) ≤ D^(9/10:ℝ)/4 := by
filter_upwards [eventually_routing_length (1/4) (51/50) (9/10) (2/25)
(by norm_num) (by norm_num) (by norm_num),
eventually_const_mul_power_le 1024 (7/10) (9/10) (by norm_num),
eventually_constant_le_power 2 (9/10) (by norm_num),
eventually_gt_atTop (1:ℝ)] with D hlen hcost htwo hD r hr hrD
have hD0 : 0 < D := by linarith
have hr2 : 2 ≤ r := htwo.trans hr
have hh : (1/4)*D^(9/10:ℝ) ≤ r := by
have hh0 := Real.rpow_nonneg hD0.le (9/10:ℝ)
linarith
have hL := hlen r hr2 hrD hh
norm_num at hL
have hL' : (routingLength r (D^(9/10:ℝ)/4) : ℝ) ≤ D^(1/5:ℝ) := by
convert hL using 1 ; ring_nf
have hsmall : D^(1/100:ℝ) ≤ D^(3/10:ℝ) := Real.rpow_le_rpow_of_exponent_le hD.le (by norm_num)
have h37 : D^(3/10:ℝ) ≤ D^(7/10:ℝ) := Real.rpow_le_rpow_of_exponent_le hD.le (by norm_num)
have hprod : (routingLength r (D^(9/10:ℝ)/4) : ℝ)^2*
(D^(1/100:ℝ)+D^(3/10:ℝ)) ≤ 2*D^(7/10:ℝ) := by
calc
_ ≤ (D^(1/5:ℝ))^2 * (2*D^(3/10:ℝ)) := by gcongr; linarith
_ = _ := by
rw [← Real.rpow_mul_natCast hD0.le]
norm_num
rw [mul_left_comm, ← Real.rpow_add hD0]
norm_num
refine ⟨hr2, ?_⟩
nlinarith only [hprod, h37, hcost]
obtain ⟨A,hA⟩ := eventually_atTop.mp hev
refine ⟨max A 2, lt_of_lt_of_le (by norm_num) (le_max_right _ _), ?_⟩
intro D hD
exact hA D ((le_max_left _ _).trans hD)
lemma eventually_reservoir_capacity (c p : ℝ) (hc : 0 < c) (hp : 0 < p) :
∀ᶠ D : ℝ in atTop, ∀ r : ℝ, 0 ≤ r → r ≤ D^(51/50:ℝ) →
(⌈8*r/(p*(c*D^(9/10:ℝ)))⌉₊ : ℝ) ≤ D^(13/100:ℝ) := by
filter_upwards [eventually_const_mul_power_le (8/(p*c)+1) (3/25) (13/100) (by norm_num),
eventually_gt_atTop (1:ℝ)] with D hbound hD r hr hrD
have hD0 : 0 < D := by linarith
have hden : 0 < p*(c*D^(9/10:ℝ)) := by positivity
have hone : 1 ≤ D^(3/25:ℝ) := Real.one_le_rpow hD.le (by norm_num)
have hx : 8*r/(p*(c*D^(9/10:ℝ))) ≤ (8/(p*c))*D^(3/25:ℝ) := by
calc
_ ≤ 8*D^(51/50:ℝ)/(p*(c*D^(9/10:ℝ))) := by gcongr
_ = _ := by
have heq : D^(3/25:ℝ) = D^(51/50:ℝ)/D^(9/10:ℝ) := by
rw [← Real.rpow_sub hD0]; norm_num
rw [heq]; ring
have hceil := Nat.ceil_lt_add_one (show 0 ≤ 8*r/(p*(c*D^(9/10:ℝ))) by positivity)
nlinarith only [hx, hceil, hone, hbound]
theorem residue_routing_margin (c p : ℝ) (hc : 0 < c) (hp : 0 < p) :
∃ D₀ : ℝ, 1 < D₀ ∧ ∀ D ≥ D₀, ∀ r rᵢ : ℝ,
0 ≤ r → r ≤ D^(51/50:ℝ) → 2 ≤ rᵢ → rᵢ ≤ r → D^(37/50:ℝ) ≤ rᵢ →
64*((routingLength rᵢ (D^(37/50:ℝ)) : ℝ)^2*
((⌈8*r/(p*(c*D^(9/10:ℝ)))⌉₊ : ℝ)+1)) ≤ D^(37/50:ℝ) := by
have hev : ∀ᶠ D : ℝ in atTop, ∀ r rᵢ : ℝ,
0 ≤ r → r ≤ D^(51/50:ℝ) → 2 ≤ rᵢ → rᵢ ≤ r → D^(37/50:ℝ) ≤ rᵢ →
64*((routingLength rᵢ (D^(37/50:ℝ)) : ℝ)^2*
((⌈8*r/(p*(c*D^(9/10:ℝ)))⌉₊ : ℝ)+1)) ≤ D^(37/50:ℝ) := by
filter_upwards [eventually_routing_length 1 (51/50) (37/50) (1/100)
(by norm_num) (by norm_num) (by norm_num),
eventually_reservoir_capacity c p hc hp,
eventually_const_mul_power_le 128 (71/100) (37/50) (by norm_num),
eventually_gt_atTop (1:ℝ)] with D hlen hcap hcost hD r rᵢ hr hrD hri2 hrir htau
have hD0 : 0 < D := by linarith
have hL := hlen rᵢ hri2 (hrir.trans hrD) (by simpa using htau)
norm_num at hL
have hk := hcap r hr hrD
have hone : 1 ≤ D^(13/100:ℝ) := Real.one_le_rpow hD.le (by norm_num)
have hprod : (routingLength rᵢ (D^(37/50:ℝ)) : ℝ)^2*
((⌈8*r/(p*(c*D^(9/10:ℝ)))⌉₊ : ℝ)+1) ≤ 2*D^(71/100:ℝ) := by
calc
_ ≤ (D^(29/100:ℝ))^2 * (2*D^(13/100:ℝ)) := by gcongr; linarith
_ = _ := by
rw [← Real.rpow_mul_natCast hD0.le]
norm_num
rw [mul_left_comm, ← Real.rpow_add hD0]
norm_num
nlinarith only [hprod, hcost]
obtain ⟨A,hA⟩ := eventually_atTop.mp hev
refine ⟨max A 2, lt_of_lt_of_le (by norm_num) (le_max_right _ _), ?_⟩
intro D hD
exact hA D ((le_max_left _ _).trans hD)
end
end ErdosGallai.Batch
namespace ErdosGallai.Batch
noncomputable section
open Finset
attribute [local instance] Classical.propDecidable
variable {V : Type} [Fintype V] [DecidableEq V]
def CutExpansionOn (P : SimpleGraph V) [DecidableRel P.Adj] (W : Finset V) (h : ℝ) : Prop :=
∀ A : Finset V, A ⊆ W → h * min (A.card : ℝ) ((W \ A).card : ℝ) ≤
((P.interedges A (W \ A)).card : ℝ)
lemma subtype_image_compl {V : Type} [_contextInstance1 : Fintype V] [_contextInstance2 : DecidableEq V] (W : Finset V) (U : Finset (W : Set V)) :
Uᶜ.image Subtype.val = W \ U.image Subtype.val := by
ext v
simp only [Finset.mem_image, Finset.mem_compl, Finset.mem_sdiff]
constructor
· rintro ⟨x,hx,rfl⟩
refine ⟨x.property,?_⟩
rintro ⟨y,hy,he⟩
exact hx (Subtype.ext he ▸ hy)
· rintro ⟨hv,hvU⟩
refine ⟨⟨v,hv⟩,?_,rfl⟩
intro hx
exact hvU ⟨⟨v,hv⟩,hx,rfl⟩
lemma induced_interedges_card (P : SimpleGraph V) [DecidableRel P.Adj]
(W : Finset V) (U : Finset (W : Set V)) :
(((P.induce (W : Set V)).interedges U Uᶜ).card : ℝ) =
((P.interedges (U.image Subtype.val) (W \ U.image Subtype.val)).card : ℝ) := by
classical
let f : ↥(W : Set V) × ↥(W : Set V) → V × V := fun e => (e.1.val,e.2.val)
have hf : Function.Injective f := by
intro a b h
apply Prod.ext <;> apply Subtype.ext
· exact congrArg Prod.fst h
· exact congrArg Prod.snd h
have heq : ((P.induce (W : Set V)).interedges U Uᶜ).image f =
P.interedges (U.image Subtype.val) (W \ U.image Subtype.val) := by
rw [← subtype_image_compl W U]
ext e
simp only [SimpleGraph.mem_interedges_iff, Finset.mem_image]
constructor
· rintro ⟨a,⟨ha,hb,hab⟩,rfl⟩
exact ⟨⟨a.1,ha,rfl⟩,⟨a.2,hb,rfl⟩,hab⟩
· rintro ⟨⟨x,hx,hxe⟩,⟨y,hy,hye⟩,he⟩
refine ⟨(x,y),⟨hx,hy,?_⟩,Prod.ext hxe hye⟩
change P.Adj x.val y.val
simpa only [hxe,hye] using he
rw [← heq, Finset.card_image_of_injective _ hf]
lemma cutExpansion_induce (P : SimpleGraph V) [DecidableRel P.Adj]
(W : Finset V) (h : ℝ) (hexp : CutExpansionOn P W h) :
CutExpansion (P.induce (W : Set V)) h := by
classical
intro U
have hsub : U.image Subtype.val ⊆ W := by
rintro v hv
obtain ⟨a,ha,rfl⟩ := Finset.mem_image.mp hv
exact a.property
have h := hexp (U.image Subtype.val) hsub
have he : W \ U.image Subtype.val = Uᶜ.image Subtype.val :=
(subtype_image_compl W U).symm
rw [he] at h
simp only [Finset.card_image_of_injective _ Subtype.val_injective] at h
rw [induced_interedges_card,he]
exact h
lemma pathInterior_map {A B : Type} [DecidableEq A] [DecidableEq B]
{H : SimpleGraph A} {J : SimpleGraph B} (f : H →g J)
(hf : Function.Injective f) {a b : A} (p : H.Walk a b) :
pathInterior (p.map f) = (pathInterior p).image f := by
classical
simp only [pathInterior, SimpleGraph.Walk.support_map]
rw [Finset.image_sdiff _ _ hf]
have hm : (p.support.map f).toFinset = p.support.toFinset.image f := by
ext v; simp
rw [hm]
simp
theorem team_routing_on_set {I T : Type} [Fintype I]
(G P : SimpleGraph V) [DecidableRel P.Adj] (hPG : P ≤ G)
(W : Finset V) (h : ℝ) (hh : 0 < h)
(hexp : CutExpansionOn P W h) (hr : 2 ≤ W.card)
(x y : I → V) (hx : ∀ i, x i ∈ W) (hy : ∀ i, y i ∈ W)
(hxy : ∀ i, x i ≠ y i) (team : I → T) (Z : I → Finset V)
(k b z : ℝ) (hk : 1 ≤ k) (hb : 1 ≤ b) (hz : 0 ≤ z)
(hload : ∀ v, (endpointLoad univ x y v : ℝ) ≤ k)
(hteam : ∀ i, ((univ.filter (fun j => team j = team i)).card : ℝ) ≤ b)
(hZ : ∀ i, ((Z i).card : ℝ) ≤ z)
(hbudget : 64 * ((routingLength W.card h : ℝ)^2 * (k+b) + z) ≤ h) :
∃ q : ∀ i, G.Walk (x i) (y i),
(∀ i, (q i).IsPath ∧ (q i).length ≤ routingLength W.card h ∧
(∀ v ∈ (q i).support, v ∈ W) ∧ (q i).edgeSet ⊆ P.edgeSet ∧
Disjoint (pathInterior (q i)) (Z i)) ∧
Pairwise (fun i j => Disjoint (q i).edgeSet (q j).edgeSet) ∧
(∀ i j, i ≠ j → team i = team j →
Disjoint (pathInterior (q i)) (pathInterior (q j))) := by
classical
let X : I → (W : Set V) := fun i => ⟨x i,hx i⟩
let Y : I → (W : Set V) := fun i => ⟨y i,hy i⟩
let Z' : I → Finset (W : Set V) := fun i => univ.filter (fun v => v.val ∈ Z i)
have hl (v : (W : Set V)) : (endpointLoad univ X Y v : ℝ) ≤ k := by
simpa only [endpointLoad,X,Y,Subtype.ext_iff] using hload v.val
have hz' : ∀ i, ((Z' i).card : ℝ) ≤ z := by
intro i
apply le_trans _ (hZ i)
have hc : (Z' i).card ≤ (Z i).card := by
apply Finset.card_le_card_of_injOn Subtype.val
· intro v hv; exact (Finset.mem_filter.mp hv).2
· exact Subtype.val_injective.injOn
exact_mod_cast hc
obtain ⟨q,hq,hd,ht⟩ := routing (P.induce (W : Set V)) h hh
(cutExpansion_induce P W h hexp) (by simpa using hr) X Y
(fun i he => hxy i (congrArg Subtype.val he)) team Z' k b z hk hb hz hl hteam hz'
(by simpa using hbudget)
let f : (P.induce (W : Set V)) →g G :=
{ toFun := Subtype.val, map_rel' := fun ha => hPG ha }
have hf : Function.Injective f := Subtype.val_injective
have hcard : Fintype.card ↥(W : Set V) = W.card := Fintype.card_coe W
let Q : ∀ i, G.Walk (x i) (y i) := fun i => (q i).map f
refine ⟨Q,?_,?_,?_⟩
· intro i
refine ⟨(hq i).1.map hf,?_,?_,?_,?_⟩
· simpa only [Q,SimpleGraph.Walk.length_map,hcard] using (hq i).2.1
· intro v hv
have hv' : v ∈ (q i).support.map f := by simpa only [Q,SimpleGraph.Walk.support_map] using hv
obtain ⟨a,ha,rfl⟩ := List.mem_map.mp hv'
exact a.property
· intro e he
rw [SimpleGraph.Walk.edgeSet_map] at he
obtain ⟨d,hd,rfl⟩ := he
induction d using Sym2.ind with
| _ a b => exact (q i).adj_of_mem_edges hd
· rw [show Q i = (q i).map f from rfl, pathInterior_map f hf]
apply Finset.disjoint_left.mpr
intro v hv hzv
obtain ⟨a,ha,rfl⟩ := Finset.mem_image.mp hv
exact Finset.disjoint_left.mp (hq i).2.2 ha (by simpa [Z',f] using hzv)
· intro i j hij
change Disjoint ((q i).map f).edgeSet ((q j).map f).edgeSet
rw [SimpleGraph.Walk.edgeSet_map,SimpleGraph.Walk.edgeSet_map,
Set.disjoint_image_iff (Sym2.map.injective hf)]
apply Set.disjoint_left.mpr
intro e he he'
exact Finset.disjoint_left.mp (hd i j hij) (by simpa using he) (by simpa using he')
· intro i j hij hteam'
change Disjoint (pathInterior ((q i).map f)) (pathInterior ((q j).map f))
rw [pathInterior_map f hf,pathInterior_map f hf,Finset.disjoint_image hf]
exact ht i j hij hteam'
theorem uniform_batch_routing :
∃ D₀ : ℝ, 1 < D₀ ∧ ∀ D ≥ D₀,
∀ (A : Type) [Fintype A] [DecidableEq A],
∀ (G P : SimpleGraph A) [DecidableRel P.Adj], P ≤ G →
∀ W : Finset A, CutExpansionOn P W (D^(9/10:ℝ)/4) →
D^(9/10:ℝ) ≤ (W.card : ℝ) → (W.card : ℝ) ≤ D^(51/50:ℝ) →
∀ (I T : Type) [Fintype I] (x y : I → A),
(∀ i, x i ∈ W) → (∀ i, y i ∈ W) → (∀ i, x i ≠ y i) →
∀ (team : I → T) (Z : I → Finset A),
(∀ v, (endpointLoad univ x y v : ℝ) ≤ D^(1/100:ℝ)) →
(∀ i, ((univ.filter (fun j => team j = team i)).card : ℝ) ≤ D^(3/10:ℝ)) →
(∀ i, ((Z i).card : ℝ) ≤ 2*D^(3/10:ℝ)) →
∃ q : ∀ i, G.Walk (x i) (y i),
(∀ i, (q i).IsPath ∧ (q i).length ≤ routingLength W.card (D^(9/10:ℝ)/4) ∧
(∀ v ∈ (q i).support, v ∈ W) ∧ (q i).edgeSet ⊆ P.edgeSet ∧
Disjoint (pathInterior (q i)) (Z i)) ∧
Pairwise (fun i j => Disjoint (q i).edgeSet (q j).edgeSet) ∧
(∀ i j, i ≠ j → team i = team j →
Disjoint (pathInterior (q i)) (pathInterior (q j))) := by
obtain ⟨D₀,hD₀,hm⟩ := batch_routing_margin
refine ⟨D₀,hD₀,?_⟩
intro D hD A _ _ G P _ hPG W hexp hr₁ hr₂ I T _ x y hx hy hxy team Z hl ht hZ
have hD1 : 1 < D := hD₀.trans_le hD
have hD0 : 0 < D := lt_trans zero_lt_one hD1
obtain ⟨hr,hbudget⟩ := hm D hD W.card hr₁ hr₂
apply team_routing_on_set G P hPG W _ (by positivity) hexp (by exact_mod_cast hr)
x y hx hy hxy team Z _ _ _ _ _ (by positivity) hl ht hZ hbudget
· exact Real.one_le_rpow hD1.le (by norm_num)
· exact Real.one_le_rpow hD1.le (by norm_num)
end
end ErdosGallai.Batch
namespace ErdosGallai.Batch
open SimpleGraph
variable {V : Type cycleUniverse1} {G : SimpleGraph V}
structure CycleVisit (G : SimpleGraph V) where
start : V
finish : V
walk : G.Walk start finish
inductive VisitChain (G : SimpleGraph V) : V → V → Type _
| single {u v : V} (p : G.Walk u v) : VisitChain G u v
| cons {u v w z : V} (p : G.Walk u v) (h : G.Adj v w)
(q : VisitChain G w z) : VisitChain G u z
namespace VisitChain
variable {u v : V}
def walk : {u v : V} → VisitChain G u v → G.Walk u v
| _, _, .single p => p
| _, _, .cons p h q => p.append (.cons h q.walk)
def visits : {u v : V} → VisitChain G u v → List (CycleVisit G)
| u, v, .single p => [⟨u,v,p⟩]
| u, _, .cons (v := v) p _ q => ⟨u,v,p⟩ :: q.visits
def links : {u v : V} → VisitChain G u v → Set (Sym2 V)
| _, _, .single _ => ∅
| _, _, .cons (v := v) (w := w) _ _ q => {s(v,w)} ∪ q.links
def switchEdges (q : VisitChain G u v) : Set (Sym2 V) :=
⋃ p ∈ q.visits, p.walk.edgeSet
lemma mem_support_iff (q : VisitChain G u v) (x : V) :
x ∈ q.walk.support ↔ ∃ p ∈ q.visits, x ∈ p.walk.support := by
induction q with
| single p => simp [walk, visits]
| cons p h q ih =>
simp only [walk, Walk.mem_support_append_iff, Walk.support_cons, List.mem_cons,
ih, visits, List.mem_cons]
constructor
· rintro (hp | rfl | ⟨r,hr,hx⟩)
· exact ⟨_, Or.inl rfl, hp⟩
· exact ⟨_, Or.inl rfl, p.end_mem_support⟩
· exact ⟨r, Or.inr hr, hx⟩
· rintro ⟨r, rfl | hr, hx⟩
· exact Or.inl hx
· exact Or.inr (Or.inr ⟨r,hr,hx⟩)
lemma isPath_of_separated (q : VisitChain G u v)
(hp : ∀ p ∈ q.visits, p.walk.IsPath)
(hd : q.visits.Pairwise (fun p r => p.walk.support.Disjoint r.walk.support)) :
q.walk.IsPath := by
induction q with
| single p => exact hp ⟨_,_,p⟩ (by simp [visits])
| cons p h q ih =>
have hpd := (List.pairwise_cons.mp hd).1
have hqt := ih (fun r hr => hp r (by simp [visits, hr]))
(List.pairwise_cons.mp hd).2
have hpt := hp ⟨_,_,p⟩ (by simp [visits])
have hdisj : p.support.Disjoint q.walk.support := by
rw [List.disjoint_left]
intro x hx hqx
obtain ⟨r,hr,hxr⟩ := q.mem_support_iff x |>.mp hqx
exact hpd r hr hx hxr
apply Walk.IsPath.mk'
simpa only [walk, Walk.support_append, Walk.support_cons, List.tail_cons]
using (List.nodup_append').mpr ⟨hpt.support_nodup, hqt.support_nodup, hdisj⟩
lemma length_visits_le (q : VisitChain G u v) : q.visits.length ≤ q.walk.length + 1 := by
induction q with
| single p => simp [visits, walk]
| cons p h q ih => simp only [visits, List.length_cons, walk, Walk.length_append,
Walk.length_cons]; omega
lemma edgeSet_eq (q : VisitChain G u v) :
q.walk.edgeSet = q.links ∪ q.switchEdges := by
induction q with
| single p => simp [walk, links, switchEdges, visits]
| cons p h q ih =>
simp only [walk, Walk.edgeSet_append, Walk.edgeSet_cons, ih, links,
switchEdges, visits]
ext e
simp only [Set.mem_union, Set.mem_singleton_iff, Set.mem_insert_iff,
Set.mem_iUnion, List.mem_cons, exists_prop, or_and_right, exists_or, exists_eq_left]
tauto
theorem close_cycle (q : VisitChain G u v) (hc : G.Adj v u)
(hp : ∀ p ∈ q.visits, p.walk.IsPath)
(hd : q.visits.Pairwise (fun p r => p.walk.support.Disjoint r.walk.support))
(hn : 3 ≤ q.visits.length) :
(Walk.cons hc q.walk).IsCycle ∧
(Walk.cons hc q.walk).edgeSet = {s(v,u)} ∪ q.links ∪ q.switchEdges ∧
3 ≤ (Walk.cons hc q.walk).length := by
have hpath := q.isPath_of_separated hp hd
have hlength := q.length_visits_le
have he : s(v,u) ∉ q.walk.edges := by
intro he
have hh := hpath.length_eq_one_of_mem_edges (Sym2.eq_swap ▸ he)
omega
refine ⟨Path.cons_isCycle ⟨q.walk,hpath⟩ hc he, ?_, ?_⟩
· rw [Walk.edgeSet_cons, q.edgeSet_eq]
ext e
simp only [Set.mem_union, Set.mem_insert_iff, Set.mem_singleton_iff]
tauto
· simp only [Walk.length_cons]
omega
end VisitChain
namespace CycleVisit
def ends (p : CycleVisit G) : Set V := {p.start, p.finish}
def interior (p : CycleVisit G) : Set V := {x | x ∈ p.walk.support} \ p.ends
lemma separated_of_interiors (p q : CycleVisit G)
(he : Disjoint p.ends q.ends)
(hpq : Disjoint p.interior q.ends) (hqp : Disjoint q.interior p.ends)
(hi : Disjoint p.interior q.interior) :
p.walk.support.Disjoint q.walk.support := by
rw [List.disjoint_left]
intro x hx hy
by_cases hpx : x ∈ p.ends
· by_cases hqx : x ∈ q.ends
· exact Set.disjoint_left.mp he hpx hqx
· exact Set.disjoint_left.mp hqp ⟨hy,hqx⟩ hpx
· by_cases hqx : x ∈ q.ends
· exact Set.disjoint_left.mp hpq ⟨hx,hpx⟩ hqx
· exact Set.disjoint_left.mp hi ⟨hx,hpx⟩ ⟨hy,hqx⟩
end CycleVisit
theorem quotient_cycle_inflation {u v : V} (q : VisitChain G u v) (hc : G.Adj v u)
(hp : ∀ p ∈ q.visits, p.walk.IsPath)
(he : q.visits.Pairwise (fun p r => Disjoint p.ends r.ends))
(hf : ∀ p ∈ q.visits, ∀ r ∈ q.visits, Disjoint p.interior r.ends)
(hi : q.visits.Pairwise (fun p r => Disjoint p.interior r.interior))
(hn : 3 ≤ q.visits.length) :
(Walk.cons hc q.walk).IsCycle ∧
(Walk.cons hc q.walk).edgeSet = {s(v,u)} ∪ q.links ∪ q.switchEdges ∧
3 ≤ (Walk.cons hc q.walk).length := by
apply q.close_cycle hc hp _ hn
have hh := he.and hi
apply hh.imp_of_mem
intro p r hpm hrm hpr
exact p.separated_of_interiors r hpr.1 (hf p hpm r hrm) (hf r hrm p hpm) hpr.2
namespace VisitChain
variable {W : Type cycleUniverse2} {Q : SimpleGraph W}
def of_walk (s t : W → V) (q : ∀ z, G.Walk (s z) (t z)) :
{a b : W} → (p : Q.Walk a b) →
(∀ d ∈ p.darts, G.Adj (t d.fst) (s d.snd)) → VisitChain G (s a) (t b)
| _, _, .nil, _ => .single (q _)
| a, b, .cons (v := c) h p, hr => .cons (q a)
(hr ⟨(a,c),h⟩ (by simp))
(of_walk s t q p (by intro d hd; exact hr d (by simp [hd])))
lemma of_walk_visits (s t : W → V) (q : ∀ z, G.Walk (s z) (t z))
{a b : W} (p : Q.Walk a b)
(hr : ∀ d ∈ p.darts, G.Adj (t d.fst) (s d.snd)) :
(of_walk s t q p hr).visits = p.support.map (fun z => (⟨s z,t z,q z⟩ : CycleVisit G)) := by
induction p with
| nil => rfl
| cons h p ih => simp [of_walk, visits, ih]
lemma of_walk_links (s t : W → V) (q : ∀ z, G.Walk (s z) (t z))
{a b : W} (p : Q.Walk a b)
(hr : ∀ d ∈ p.darts, G.Adj (t d.fst) (s d.snd)) :
(of_walk s t q p hr).links = {e | ∃ d ∈ p.darts, e = s(t d.fst,s d.snd)} := by
induction p with
| nil => ext e; simp [of_walk, links]
| cons h p ih =>
ext e
simp [of_walk, links, ih, ]
lemma of_walk_switchEdges (s t : W → V) (q : ∀ z, G.Walk (s z) (t z))
{a b : W} (p : Q.Walk a b)
(hr : ∀ d ∈ p.darts, G.Adj (t d.fst) (s d.snd)) :
(of_walk s t q p hr).switchEdges = ⋃ z ∈ p.support, (q z).edgeSet := by
rw [switchEdges, of_walk_visits]
ext e
simp only [Set.mem_iUnion, List.mem_map, exists_prop]
constructor
· rintro ⟨r,⟨z,hz,rfl⟩,he⟩
exact ⟨z,hz,he⟩
· rintro ⟨z,hz,he⟩
exact ⟨⟨s z,t z,q z⟩,⟨z,hz,rfl⟩,he⟩
end VisitChain
theorem lift_quotient_cycle {W : Type cycleUniverse3} {Q : SimpleGraph W}
(s t : W → V) (q : ∀ z, G.Walk (s z) (t z))
{a : W} (p : Q.Walk a a) (hp : p.IsCycle)
(hr : ∀ d ∈ p.dropLast.darts, G.Adj (t d.fst) (s d.snd))
(hc : G.Adj (t p.penultimate) (s a))
(hq : ∀ z ∈ p.dropLast.support, (q z).IsPath)
(hsep : ∀ z ∈ p.dropLast.support, ∀ w ∈ p.dropLast.support,
z ≠ w → (q z).support.Disjoint (q w).support) :
∃ c : G.Walk (t p.penultimate) (t p.penultimate), c.IsCycle ∧
c.edgeSet = {s(t p.penultimate,s a)} ∪
{e | ∃ d ∈ p.dropLast.darts, e = s(t d.fst,s d.snd)} ∪
(⋃ z ∈ p.dropLast.support, (q z).edgeSet) := by
let chain := VisitChain.of_walk s t q p.dropLast hr
have hv : chain.visits = p.dropLast.support.map (fun z => (⟨s z,t z,q z⟩ : CycleVisit G)) :=
VisitChain.of_walk_visits s t q p.dropLast hr
have hpaths : ∀ v ∈ chain.visits, v.walk.IsPath := by
intro v hvv
rw [hv] at hvv
obtain ⟨z,hz,rfl⟩ := List.mem_map.mp hvv
exact hq z hz
have hpair : chain.visits.Pairwise (fun v w => v.walk.support.Disjoint w.walk.support) := by
rw [hv, List.pairwise_map]
apply (List.pairwise_iff_getElem).mpr
intro i j hi hj hij
have hne : p.dropLast.support[i] ≠ p.dropLast.support[j] := by
intro he
have hij' := hp.isPath_dropLast.support_nodup.getElem_inj_iff.mp he
omega
exact hsep _ (List.getElem_mem _) _ (List.getElem_mem _) hne
have hn : 3 ≤ chain.visits.length := by
rw [hv, List.length_map, Walk.length_support, Walk.length_dropLast]
have := hp.three_le_length
omega
obtain ⟨hcycle,hedges,_⟩ := chain.close_cycle hc hpaths hpair hn
refine ⟨Walk.cons hc chain.walk,hcycle,?_⟩
rw [hedges, VisitChain.of_walk_links, VisitChain.of_walk_switchEdges]
noncomputable section
attribute [local instance] Classical.propDecidable
theorem orient_edge_representatives {W : Type cycleUniverse4} {Q : SimpleGraph W}
(projMap : V → W) (S : Set (Sym2 V)) (hSG : S ⊆ G.edgeSet)
(hrep : ∀ e ∈ Q.edgeSet, ∃ f ∈ S, Sym2.map projMap f = e) :
∃ R : Q.Dart → G.Dart, ∀ d,
(R d).edge ∈ S ∧ projMap (R d).fst = d.fst ∧ projMap (R d).snd = d.snd := by
have hex : ∀ d : Q.Dart, ∃ r : G.Dart,
r.edge ∈ S ∧ projMap r.fst = d.fst ∧ projMap r.snd = d.snd := by
intro d
obtain ⟨f,hf,hmap⟩ := hrep d.edge d.edge_mem
induction f using Sym2.ind with
| _ x y =>
have hadj : G.Adj x y := hSG hf
change s(projMap x,projMap y) = s(d.fst,d.snd) at hmap
rcases Sym2.eq_iff.mp hmap with he | he
· exact ⟨⟨(x,y),hadj⟩,hf,he.1,he.2⟩
· refine ⟨⟨(y,x),hadj.symm⟩,?_,he.2,he.1⟩
change s(y,x) ∈ S
simpa only [Sym2.eq_swap] using hf
exact Classical.axiomOfChoice hex
def portFrom {A : Type cycleUniverse5} {W : Type cycleUniverse6} (L : List A) (f : A → W) (g : A → V)
(v₀ : V) (z : W) : V :=
if h : ∃ d ∈ L, f d = z then g h.choose else v₀
lemma portFrom_on {A : Type cycleUniverse7} {W : Type cycleUniverse8} (L : List A) (f : A → W) (g : A → V)
(v₀ : V) (hn : (L.map f).Nodup) {d : A} (hd : d ∈ L) :
portFrom L f g v₀ (f d) = g d := by
have hex : ∃ e ∈ L, f e = f d := ⟨d,hd,rfl⟩
rw [portFrom, dite_eq_left hex]
congr 1
exact List.inj_on_of_nodup_map hn hex.choose_spec.1 hd hex.choose_spec.2
theorem choose_cycle_ports {W : Type cycleUniverse9} {Q : SimpleGraph W}
(projMap : V → W) (R : Q.Dart → G.Dart)
(hprojMap : ∀ d, projMap (R d).fst = d.fst ∧ projMap (R d).snd = d.snd)
{a : W} (p : Q.Walk a a) (hp : p.IsCycle) (v₀ : V) :
∃ s t : W → V,
(∀ d ∈ p.darts, t d.fst = (R d).fst ∧ s d.snd = (R d).snd) ∧
(∀ z ∈ p.dropLast.support, projMap (s z) = z ∧ projMap (t z) = z) := by
let s := portFrom p.darts (fun d => d.snd) (fun d => (R d).snd) v₀
let t := portFrom p.darts (fun d => d.fst) (fun d => (R d).fst) v₀
have hnf : (p.darts.map (fun d => d.fst)).Nodup := by
rw [Walk.map_fst_darts]
exact hp.nodup_dropLast_support
have hns : (p.darts.map (fun d => d.snd)).Nodup := by
rw [Walk.map_snd_darts]
exact hp.support_nodup
have ht : ∀ d ∈ p.darts, t d.fst = (R d).fst := fun d hd =>
portFrom_on _ _ _ _ hnf hd
have hs : ∀ d ∈ p.darts, s d.snd = (R d).snd := fun d hd =>
portFrom_on _ _ _ _ hns hd
refine ⟨s,t,fun d hd => ⟨ht d hd,hs d hd⟩,?_⟩
intro z hz
have hz' : z ∈ p.support.dropLast := by
rw [← p.support_dropLast hp.not_nil]
exact hz
have hzt : z ∈ p.support.tail :=
p.tail_support_perm_dropLast_support.mem_iff.mpr hz'
have hzf : z ∈ p.darts.map (fun d => d.fst) := by rwa [Walk.map_fst_darts]
have hzs : z ∈ p.darts.map (fun d => d.snd) := by rwa [Walk.map_snd_darts]
obtain ⟨d,hd,he⟩ := List.mem_map.mp hzf
obtain ⟨e,he',hee⟩ := List.mem_map.mp hzs
exact ⟨by rw [← hee,hs e he']; exact (hprojMap e).2,
by rw [← he,ht d hd]; exact (hprojMap d).1⟩
lemma last_dart_mem {W : Type cycleUniverse10} {Q : SimpleGraph W} {a b : W}
(p : Q.Walk a b) (hp : ¬p.Nil) :
(⟨(p.penultimate,b),p.adj_penultimate hp⟩ : Q.Dart) ∈ p.darts := by
have he := congrArg Walk.darts (p.concat_dropLast (p.adj_penultimate hp))
rw [Walk.darts_concat] at he
rw [← he]
simp
lemma cycle_darts_split {W : Type cycleUniverse11} {Q : SimpleGraph W} {a b : W}
(p : Q.Walk a b) (hp : ¬p.Nil) :
p.darts = p.dropLast.darts ++ [⟨(p.penultimate,b),p.adj_penultimate hp⟩] := by
have he := congrArg Walk.darts (p.concat_dropLast (p.adj_penultimate hp))
simpa only [Walk.darts_concat, List.concat_eq_append] using he.symm
theorem inflate_represented_cycle {W : Type cycleUniverse12} {Q : SimpleGraph W}
(R : Q.Dart → G.Dart) (s t : W → V)
{a : W} (p : Q.Walk a a) (hp : p.IsCycle)
(hports : ∀ d ∈ p.darts, t d.fst = (R d).fst ∧ s d.snd = (R d).snd)
(q : ∀ z, G.Walk (s z) (t z))
(hq : ∀ z ∈ p.dropLast.support, (q z).IsPath)
(hsep : ∀ z ∈ p.dropLast.support, ∀ w ∈ p.dropLast.support,
z ≠ w → (q z).support.Disjoint (q w).support) :
∃ (v : V) (c : G.Walk v v), c.IsCycle ∧
c.edgeSet = {e | ∃ d ∈ p.darts, e = (R d).edge} ∪
(⋃ z ∈ p.dropLast.support, (q z).edgeSet) := by
let last : Q.Dart := ⟨(p.penultimate,a),p.adj_penultimate hp.not_nil⟩
have hlast : last ∈ p.darts := last_dart_mem p hp.not_nil
have hsub : p.dropLast.darts ⊆ p.darts := by
rw [Walk.darts_dropLast]; exact List.dropLast_subset _
have hed : ∀ d ∈ p.darts, s(t d.fst,s d.snd) = (R d).edge := by
intro d hd
rw [(hports d hd).1,(hports d hd).2]
rfl
have hadj : ∀ d ∈ p.darts, G.Adj (t d.fst) (s d.snd) := by
intro d hd
rw [(hports d hd).1,(hports d hd).2]
exact (R d).adj
obtain ⟨c,hc,he⟩ := lift_quotient_cycle s t q p hp
(fun d hd => hadj d (hsub hd)) (hadj last hlast) hq hsep
refine ⟨_,c,hc,?_⟩
rw [he]
have hlinks : {s(t p.penultimate,s a)} ∪
{e | ∃ d ∈ p.dropLast.darts, e = s(t d.fst,s d.snd)} =
{e | ∃ d ∈ p.darts, e = (R d).edge} := by
ext e
simp only [Set.mem_union, Set.mem_singleton_iff, Set.mem_ofPred_eq]
constructor
· rintro (rfl | ⟨d,hd,rfl⟩)
· exact ⟨last,hlast,hed last hlast⟩
· exact ⟨d,hsub hd,hed d (hsub hd)⟩
· rintro ⟨d,hd,rfl⟩
rw [cycle_darts_split p hp.not_nil] at hd
simp only [List.mem_append,List.mem_singleton] at hd
rcases hd with hd | rfl
· exact Or.inr ⟨d,hd,(hed d (hsub hd)).symm⟩
· exact Or.inl (hed last hlast).symm
rw [hlinks]
theorem interiors_disjoint_across_routers {I : Type cycleUniverse13} {R : Type cycleUniverse14}
(U : R → Set V) (hi : Pairwise (fun r s => Disjoint (U r) (U s)))
(router : I → R) (A : I → Set V)
(hA : ∀ i, A i ⊆ U (router i))
(hteam : ∀ i j, i ≠ j → router i = router j → Disjoint (A i) (A j)) :
Pairwise (fun i j => Disjoint (A i) (A j)) := by
intro i j hij
by_cases hr : router i = router j
· exact hteam i j hij hr
· exact (hi hr).mono (hA i) (hA j)
def cyclePortSet {W : Type cycleUniverse15} (S : Set W) (s t : W → V) : Set V :=
{v | ∃ z ∈ S, v = s z ∨ v = t z}
def visitInterior {W : Type cycleUniverse16} (s t : W → V) (q : ∀ z, G.Walk (s z) (t z))
(z : W) : Set V := {x | x ∈ (q z).support ∧ x ≠ s z ∧ x ≠ t z}
theorem switch_supports_separated {W : Type cycleUniverse17}
(S : Set W) (projMap : V → W) (s t : W → V)
(q : ∀ z, G.Walk (s z) (t z))
(hproj : ∀ z ∈ S, projMap (s z) = z ∧ projMap (t z) = z)
(havoid : ∀ z ∈ S, Disjoint (visitInterior s t q z) (cyclePortSet S s t))
(hinter : ∀ z ∈ S, ∀ w ∈ S, z ≠ w →
Disjoint (visitInterior s t q z) (visitInterior s t q w)) :
∀ z ∈ S, ∀ w ∈ S, z ≠ w → (q z).support.Disjoint (q w).support := by
intro z hz w hw hzw
rw [List.disjoint_left]
intro x hx hy
by_cases hxend : x = s z ∨ x = t z
· have hxZ : x ∈ cyclePortSet S s t := ⟨z,hz,hxend⟩
by_cases hyend : x = s w ∨ x = t w
· have hxprojMap : projMap x = z := by rcases hxend with rfl | rfl <;> simp_all
have hyprojMap : projMap x = w := by rcases hyend with rfl | rfl <;> simp_all
exact hzw (hxprojMap.symm.trans hyprojMap)
· exact Set.disjoint_left.mp (havoid w hw)
⟨hy,fun he => hyend (Or.inl he),fun he => hyend (Or.inr he)⟩ hxZ
· have hxI : x ∈ visitInterior s t q z :=
⟨hx,fun he => hxend (Or.inl he),fun he => hxend (Or.inr he)⟩
by_cases hyend : x = s w ∨ x = t w
· exact Set.disjoint_left.mp (havoid z hz) hxI ⟨w,hw,hyend⟩
· exact Set.disjoint_left.mp (hinter z hz w hw hzw) hxI
⟨hy,fun he => hyend (Or.inl he),fun he => hyend (Or.inr he)⟩
theorem cyclePortSet_eq_representative_vertices {W : Type cycleUniverse18} {Q : SimpleGraph W}
(R : Q.Dart → G.Dart) (s t : W → V)
{a : W} (p : Q.Walk a a) (hp : p.IsCycle)
(hports : ∀ d ∈ p.darts, t d.fst = (R d).fst ∧ s d.snd = (R d).snd) :
cyclePortSet {z | z ∈ p.dropLast.support} s t =
{v | ∃ d ∈ p.darts, v = (R d).fst ∨ v = (R d).snd} := by
have hmF : p.darts.map (fun d => d.fst) = p.dropLast.support := by
rw [Walk.map_fst_darts, p.support_dropLast hp.not_nil]
have hmS : ∀ z, z ∈ p.darts.map (fun d => d.snd) ↔ z ∈ p.dropLast.support := by
intro z
rw [Walk.map_snd_darts, p.support_dropLast hp.not_nil]
exact p.tail_support_perm_dropLast_support.mem_iff
ext v
constructor
· rintro ⟨z,hz,hv | hv⟩
· obtain ⟨d,hd,hds⟩ := List.mem_map.mp ((hmS z).mpr hz)
exact ⟨d,hd,Or.inr (hv.trans (by rw [← hds]; exact (hports d hd).2))⟩
· have hz' : z ∈ p.darts.map (fun d => d.fst) := by rwa [hmF]
obtain ⟨d,hd,hdf⟩ := List.mem_map.mp hz'
exact ⟨d,hd,Or.inl (hv.trans (by rw [← hdf]; exact (hports d hd).1))⟩
· rintro ⟨d,hd,hv | hv⟩
· refine ⟨d.fst,?_,Or.inr (hv.trans (hports d hd).1.symm)⟩
rw [← hmF]
exact List.mem_map.mpr ⟨d,hd,rfl⟩
· exact ⟨d.snd,(hmS _).mp (List.mem_map.mpr ⟨d,hd,rfl⟩),
Or.inl (hv.trans (hports d hd).2.symm)⟩
theorem complete_batch_cycle {W : Type cycleUniverse19} {Ridx : Type cycleUniverse20} {Q : SimpleGraph W}
(projMap : V → W) (R : Q.Dart → G.Dart)
(_hprojMap : ∀ d, projMap (R d).fst = d.fst ∧ projMap (R d).snd = d.snd)
{a : W} (p : Q.Walk a a) (hp : p.IsCycle)
(s t : W → V)
(hports : ∀ d ∈ p.darts, t d.fst = (R d).fst ∧ s d.snd = (R d).snd)
(hproj : ∀ z ∈ p.dropLast.support, projMap (s z) = z ∧ projMap (t z) = z)
(q : ∀ z, G.Walk (s z) (t z))
(hq : ∀ z ∈ p.dropLast.support, (q z).IsPath)
(U : Ridx → Set V) (hU : Pairwise (fun i j => Disjoint (U i) (U j)))
(router : {z // z ∈ p.dropLast.support} → Ridx)
(hroute : ∀ z : {z // z ∈ p.dropLast.support},
visitInterior s t q z ⊆ U (router z))
(hteam : ∀ z w : {z // z ∈ p.dropLast.support}, z ≠ w →
router z = router w → Disjoint (visitInterior s t q z) (visitInterior s t q w))
(havoid : ∀ z ∈ p.dropLast.support, Disjoint (visitInterior s t q z)
{v | ∃ d ∈ p.darts, v = (R d).fst ∨ v = (R d).snd}) :
∃ (v : V) (c : G.Walk v v), c.IsCycle ∧
c.edgeSet = {e | ∃ d ∈ p.darts, e = (R d).edge} ∪
(⋃ z ∈ p.dropLast.support, (q z).edgeSet) := by
have hinter := interiors_disjoint_across_routers U hU router
(fun z => visitInterior s t q z) hroute hteam
apply inflate_represented_cycle R s t p hp hports q hq
apply switch_supports_separated {z | z ∈ p.dropLast.support} projMap s t q hproj
· intro z hz
rw [cyclePortSet_eq_representative_vertices R s t p hp hports]
exact havoid z hz
· intro z hz w hw hzw
exact hinter (show (⟨z,hz⟩ : {z // z ∈ p.dropLast.support}) ≠ ⟨w,hw⟩ from
fun he => hzw (congrArg Subtype.val he))
end
end ErdosGallai.Batch
end
end
end
end OAI