openAI-math-dataset / lean /OAI /SetTheory /PartitionPrinciple /Transfinite /CoinitialityPreservation.lean
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Sync from openai/math@faee2cf485a8 (part 25)
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import OAI.SetTheory.PartitionPrinciple.Geometry.FinalProfilePersistence
namespace OAI
section
namespace PartitionPilot.Compression.RecursiveMaps.Chronological
universe u v w
theorem all_filters_of_countable {A : Type u} [Countable A] (P : MeetOrder A) :
AllFiltersCountable P := fun F =>
countableBelow_of_countable F F.mem (Set.to_countable _) (fun _ h => h)
theorem all_filters_of_countable_cover {A : Type u} {I : Type v} [Countable I]
{P : MeetOrder A} (Space : I → Type w) (orders : ∀ i, MeetOrder (Space i))
(copy : ∀ i, MeetEmbedding (orders i) P)
(cover : ∀ x, ∃ i y, (copy i).toFun y = x)
(small : ∀ i, AllFiltersCountable (orders i)) : AllFiltersCountable P := by
intro F
apply countableBelow_union F F.mem (fun i x => F.mem x ∧ ∃ y, (copy i).toFun y = x)
· intro x positive
rcases cover x with ⟨i, y, eq⟩
exact ⟨i, positive, y, eq⟩
· intro i
exact countableBelow_copy (copy i) F (small i)
theorem all_filters_of_surjective {A : Type u} {B : Type v}
{P : MeetOrder A} {Q : MeetOrder B} (e : MeetEmbedding P Q)
(onto : Function.Surjective e.toFun) (small : AllFiltersCountable P) : AllFiltersCountable Q := by
intro F
exact countableBelow_mono F (countableBelow_copy e F small) (fun x hx => ⟨hx, onto x⟩)
def twoLayerBirth {O : Type u} {N : Type v} : O ⊕ N → ULift.{max u v} Nat
| .inl _ => ⟨0⟩
| .inr _ => ⟨1⟩
theorem all_filters_of_separated_sum {O N I : Type u} {P : MeetOrder O}
(Q : MeetOrder (O ⊕ N)) (old : MeetEmbedding P Q)
(old_eq : ∀ x, old.toFun x = .inl x)
(Space : I → Type u) (orders : ∀ i, MeetOrder (Space i))
(copy : ∀ i, MeetEmbedding (orders i) Q) (component : N → I)
(cover : ∀ x, ∃ y, (copy (component x)).toFun y = .inr x)
(separated : ∀ x y, component x ≠ component y →
OldBridge (P := Q) twoLayerBirth ⟨1⟩ (.inr x) (.inr y))
(oldSmall : AllFiltersCountable P) (copySmall : ∀ i, AllFiltersCountable (orders i)) :
AllFiltersCountable Q := by
classical
let : WellFoundedLT (ULift.{u} Nat) := InvImage.wf ULift.down Nat.lt_wfRel.wf
intro F
have fresh : CountableBelow F
(fun x => Essential twoLayerBirth F x ∧ ∃ y, Sum.inr y = x) := by
by_cases inhabited : ∃ x : N, Essential twoLayerBirth F (.inr x)
· rcases inhabited with ⟨x, hx⟩
apply countableBelow_mono F (countableBelow_copy (copy (component x)) F (copySmall _))
rintro y ⟨hy, z, rfl⟩
have same : component z = component x := by
by_contra different
exact essentials_no_bridge twoLayerBirth F ⟨1⟩ (.inr z) (.inr x) hy hx rfl rfl
(separated z x different)
have covered := cover z
rw [same] at covered
exact ⟨hy.1, covered⟩
· exact countableBelow_empty F _ (by
rintro x ⟨hx, y, rfl⟩
exact inhabited ⟨y, hx⟩)
apply countable_basis_of_layers twoLayerBirth F (Set.to_countable _)
rintro ⟨s⟩
cases s with
| zero =>
apply countableBelow_mono F (countableBelow_copy old F oldSmall)
rintro x ⟨hx, born⟩
cases x with
| inl x => exact ⟨hx.1, x, old_eq x⟩
| inr x => exact False.elim (Nat.one_ne_zero (congrArg ULift.down born))
| succ s =>
apply countableBelow_mono F fresh
rintro x ⟨hx, born⟩
cases x with
| inl x => exact False.elim (Nat.noConfusion (congrArg ULift.down born))
| inr x => exact ⟨hx, x, rfl⟩
end PartitionPilot.Compression.RecursiveMaps.Chronological
end
end OAI