openAI-math-dataset / lean /OAI /Computability /PerfectCompleteness /Decoding /CanonicalUpperDirectionSplit.lean
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import OAI.Computability.PerfectCompleteness.Foundations.CanonicalDirections
import OAI.Computability.PerfectCompleteness.Foundations.QuarterBalanceLemmas
import OAI.Computability.PerfectCompleteness.Foundations.TupleIndexEmitterLemmas
namespace OAI
section
namespace PerfectCompleteness.CanonicalUpperDirectionSplit
noncomputable section
open scoped Classical
open UniqueGamesTheorem.Foundations.Games
variable {n : Nat}
abbrev Complement (rows : Nat → Nat) (upper : Fin n) :=
FiniteProductSplit.Others
(Ω := fun level : Fin n => PrefixTests.LevelDirection rows level) upper
def splitEquiv (rows : Nat → Nat) (upper : Fin n) :
CanonicalDirections.Tuple rows n ≃
PrefixTests.LevelDirection rows upper × Complement rows upper :=
Equiv.piSplitAt upper (fun level => PrefixTests.LevelDirection rows level)
def complement (rows : Nat → Nat) (upper : Fin n)
(directions : CanonicalDirections.Tuple rows n) : Complement rows upper :=
(splitEquiv rows upper directions).2
def assemble (rows : Nat → Nat) (upper : Fin n)
(direction : PrefixTests.LevelDirection rows upper) (rest : Complement rows upper) :
CanonicalDirections.Tuple rows n :=
(splitEquiv rows upper).symm (direction, rest)
@[simp] theorem split_selected (rows : Nat → Nat) (upper : Fin n)
(directions : CanonicalDirections.Tuple rows n) :
(splitEquiv rows upper directions).1 = directions upper := rfl
@[simp] theorem complement_apply (rows : Nat → Nat) (upper : Fin n)
(directions : CanonicalDirections.Tuple rows n) (i : {i : Fin n // i ≠ upper}) :
complement rows upper directions i = directions i.val := rfl
@[simp] theorem assemble_at_upper (rows : Nat → Nat) (upper : Fin n)
(direction : PrefixTests.LevelDirection rows upper) (rest : Complement rows upper) :
assemble rows upper direction rest upper = direction := by
exact congrArg Prod.fst ((splitEquiv rows upper).apply_symm_apply (direction, rest))
@[simp] theorem assemble_at_other (rows : Nat → Nat) (upper : Fin n)
(direction : PrefixTests.LevelDirection rows upper) (rest : Complement rows upper)
(i : Fin n) (hne : i ≠ upper) :
assemble rows upper direction rest i = rest ⟨i, hne⟩ := by
exact congrArg
(fun z : PrefixTests.LevelDirection rows upper × Complement rows upper => z.2 ⟨i, hne⟩)
((splitEquiv rows upper).apply_symm_apply (direction, rest))
theorem assemble_split (rows : Nat → Nat) (upper : Fin n)
(directions : CanonicalDirections.Tuple rows n) :
assemble rows upper (directions upper) (complement rows upper directions) = directions :=
(splitEquiv rows upper).symm_apply_apply directions
theorem lower_preserved (rows : Nat → Nat) (upper lower : Fin n) (hne : lower ≠ upper)
(direction : PrefixTests.LevelDirection rows upper)
(directions : CanonicalDirections.Tuple rows n) :
assemble rows upper direction (complement rows upper directions) lower = directions lower := by
rw [assemble_at_other rows upper direction (complement rows upper directions) lower hne]
rfl
def complementLaw (rows : Nat → Nat) (hrows : ∀ k, 0 < rows (k + 1)) (upper : Fin n) :
FiniteDistribution (Complement rows upper) :=
FiniteProductSplit.otherLaw (CanonicalDirections.levelLaw rows hrows) upper
theorem split_law (rows : Nat → Nat) (hrows : ∀ k, 0 < rows (k + 1)) (upper : Fin n) :
(CanonicalDirections.law rows n hrows).pushforward (splitEquiv rows upper) =
(CanonicalDirections.levelLaw rows hrows upper).product (complementLaw rows hrows upper) :=
FiniteProductSplit.split_law (CanonicalDirections.levelLaw rows hrows) upper
theorem assemble_law (rows : Nat → Nat) (hrows : ∀ k, 0 < rows (k + 1)) (upper : Fin n) :
((CanonicalDirections.levelLaw rows hrows upper).product
(complementLaw rows hrows upper)).pushforward
(fun z => assemble rows upper z.1 z.2) = CanonicalDirections.law rows n hrows := by
have h := congrArg
(fun μ : FiniteDistribution (PrefixTests.LevelDirection rows upper × Complement rows upper) =>
μ.pushforward (splitEquiv rows upper).symm) (split_law rows hrows upper)
rw [FiniteDistribution.pushforward_comp] at h
have hid : (fun directions : CanonicalDirections.Tuple rows n =>
(splitEquiv rows upper).symm (splitEquiv rows upper directions)) = id := by
funext directions
exact (splitEquiv rows upper).symm_apply_apply directions
rw [hid, FiniteDistribution.pushforward_id] at h
exact h.symm
theorem selected_law (rows : Nat → Nat) (hrows : ∀ k, 0 < rows (k + 1)) (upper : Fin n) :
(CanonicalDirections.law rows n hrows).pushforward (fun directions => directions upper) =
CanonicalDirections.levelLaw rows hrows upper :=
FiniteProduct.eval_pushforward (CanonicalDirections.levelLaw rows hrows) upper
theorem probability_split (rows : Nat → Nat) (hrows : ∀ k, 0 < rows (k + 1))
(upper : Fin n) (event : CanonicalDirections.Tuple rows n → Bool) :
(CanonicalDirections.law rows n hrows).probability event =
((CanonicalDirections.levelLaw rows hrows upper).product
(complementLaw rows hrows upper)).probability
(fun z => event (assemble rows upper z.1 z.2)) := by
rw [← assemble_law rows hrows upper, FiniteDistribution.probability_pushforward]
theorem probability_complement_first (rows : Nat → Nat)
(hrows : ∀ k, 0 < rows (k + 1)) (upper : Fin n)
(event : CanonicalDirections.Tuple rows n → Bool) :
(CanonicalDirections.law rows n hrows).probability event =
(complementLaw rows hrows upper).expectation (fun rest =>
(CanonicalDirections.levelLaw rows hrows upper).probability
(fun direction => event (assemble rows upper direction rest))) := by
rw [probability_split rows hrows upper]
exact UsefulAdvice.product_probability_advice_first _ _ _
theorem lower_choice_preserved {branch : Nat → Nat} (rows : Nat → Nat)
(leaf : RecursiveSpaces.Slots branch n) (upper lower : Fin n) (hne : lower ≠ upper)
(direction : PrefixTests.LevelDirection rows upper)
(directions : CanonicalDirections.Tuple rows n) :
PrefixTests.choiceAt rows leaf lower
(assemble rows upper direction (complement rows upper directions) lower) =
PrefixTests.choiceAt rows leaf lower (directions lower) := by
rw [lower_preserved rows upper lower hne direction directions]
end
end PerfectCompleteness.CanonicalUpperDirectionSplit
end
end OAI