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Add lean source and binary files (part 61)
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import Mathlib
import OAI.Computability.DirectedFeedback.Games.Generator
namespace OAI
namespace DFVSGames.Foundations.PCP.PortTables
open PoweringWalks
abbrev Label := GraphTables.Label
def rowIndex (vertices ports : Nat) :
Fin vertices × Fin ports ≃ Fin (vertices * ports) := finProdFinEquiv
@[simp] theorem rowIndex_val (n d : Nat) (e : Fin n × Fin d) :
(rowIndex n d e).val = e.2.val + d * e.1.val := rfl
structure Table (vertices ports : Nat) where
reverseIndex : Vector (Fin (vertices * ports)) (vertices * ports)
relations : Vector GraphTables.RelationTable (vertices * ports)
involutive : Function.Involutive
(fun i : Fin (vertices * ports) => reverseIndex[i])
transpose : ∀ (i : Fin (vertices * ports)) (a b : Label),
GraphTables.relationAt relations[reverseIndex[i]] b a =
GraphTables.relationAt relations[i] a b
variable {n d : Nat}
def rotation (table : Table n d) (e : Fin n × Fin d) : Fin n × Fin d :=
(rowIndex n d).symm table.reverseIndex[rowIndex n d e]
def accepts (table : Table n d) (e : Fin n × Fin d) (a b : Label) : Bool :=
GraphTables.relationAt table.relations[rowIndex n d e] a b
@[simp] theorem rowIndex_rotation (table : Table n d) (e : Fin n × Fin d) :
rowIndex n d (rotation table e) = table.reverseIndex[rowIndex n d e] := by
exact (rowIndex n d).apply_symm_apply _
theorem rotation_involutive (table : Table n d) : Function.Involutive (rotation table) := by
intro e
simp only [rotation, Equiv.apply_symm_apply]
exact (congrArg (rowIndex n d).symm (table.involutive (rowIndex n d e))).trans
((rowIndex n d).symm_apply_apply e)
theorem accepts_rotation (table : Table n d) (e : Fin n × Fin d) (a b : Label) :
accepts table (rotation table e) b a = accepts table e a b := by
simpa only [accepts, rowIndex_rotation] using table.transpose (rowIndex n d e) a b
def portGraph (table : Table n d) : PortGraph (Fin n) (Fin d) where
rot :=
{ toFun := rotation table
invFun := rotation table
left_inv := rotation_involutive table
right_inv := rotation_involutive table }
rot_involutive := rotation_involutive table
@[simp] theorem portGraph_rot (table : Table n d) (e : Fin n × Fin d) :
(portGraph table).rot e = rotation table e := rfl
def baseGraph (table : Table n d) : ConstraintGraph (Fin n) (Fin n × Fin d) Label where
reverse := (portGraph table).rot
reverse_involutive := rotation_involutive table
tail := Prod.fst
accepts := accepts table
reverse_accepts := accepts_rotation table
@[simp] theorem baseGraph_reverse (table : Table n d) (e : Fin n × Fin d) :
(baseGraph table).reverse e = rotation table e := rfl
@[simp] theorem baseGraph_tail (table : Table n d) (e : Fin n × Fin d) :
(baseGraph table).tail e = e.1 := rfl
@[simp] theorem baseGraph_head (table : Table n d) (e : Fin n × Fin d) :
(baseGraph table).head e = (rotation table e).1 := rfl
@[simp] theorem baseGraph_accepts (table : Table n d) (e : Fin n × Fin d) (a b : Label) :
(baseGraph table).accepts e a b = accepts table e a b := rfl
def ofPortGraph (G : PortGraph (Fin n) (Fin d))
(predicate : (Fin n × Fin d) → Label → Label → Bool)
(htranspose : ∀ e a b, predicate (G.rot e) b a = predicate e a b) : Table n d where
reverseIndex := Vector.ofFn (fun i => rowIndex n d (G.rot ((rowIndex n d).symm i)))
relations := Vector.ofFn (fun i => GraphTables.relationOf (predicate ((rowIndex n d).symm i)))
involutive := by
intro i
simp only [Fin.getElem_fin, Vector.getElem_ofFn, Fin.eta,
Equiv.symm_apply_apply]
exact (congrArg (rowIndex n d) (G.rot_involutive ((rowIndex n d).symm i))).trans
((rowIndex n d).apply_symm_apply i)
transpose := by
intro i a b
simp only [Fin.getElem_fin, Vector.getElem_ofFn, Fin.eta,
Equiv.symm_apply_apply, GraphTables.relationAt_relationOf]
exact htranspose ((rowIndex n d).symm i) a b
@[simp] theorem rotation_ofPortGraph (G : PortGraph (Fin n) (Fin d))
(predicate : (Fin n × Fin d) → Label → Label → Bool)
(htranspose : ∀ e a b, predicate (G.rot e) b a = predicate e a b)
(e : Fin n × Fin d) : rotation (ofPortGraph G predicate htranspose) e = G.rot e := by
simp only [rotation, ofPortGraph, Fin.getElem_fin, Vector.getElem_ofFn, Fin.eta,
Equiv.symm_apply_apply]
@[simp] theorem accepts_ofPortGraph (G : PortGraph (Fin n) (Fin d))
(predicate : (Fin n × Fin d) → Label → Label → Bool)
(htranspose : ∀ e a b, predicate (G.rot e) b a = predicate e a b)
(e : Fin n × Fin d) (a b : Label) :
accepts (ofPortGraph G predicate htranspose) e a b = predicate e a b := by
simp only [accepts, ofPortGraph, Fin.getElem_fin, Vector.getElem_ofFn, Fin.eta,
Equiv.symm_apply_apply, GraphTables.relationAt_relationOf]
def flatRows (table : Table n d) : GraphTables.Rows n (n * d) :=
Vector.ofFn (fun i =>
⟨((rowIndex n d).symm i).1, table.reverseIndex[i], table.relations[i]⟩)
@[simp] theorem reverseAt_flatRows (table : Table n d) (i : Fin (n * d)) :
GraphTables.reverseAt (flatRows table) i = table.reverseIndex[i] := by
simp [GraphTables.reverseAt, flatRows]
@[simp] theorem acceptsAt_flatRows (table : Table n d) (i : Fin (n * d)) (a b : Label) :
GraphTables.acceptsAt (flatRows table) i a b = GraphTables.relationAt table.relations[i] a b := by
simp [GraphTables.acceptsAt, flatRows]
theorem flatRows_valid (table : Table n d) : GraphTables.Valid (flatRows table) := by
constructor
· intro i
simpa only [reverseAt_flatRows] using table.involutive i
· intro i a b
simpa only [reverseAt_flatRows, acceptsAt_flatRows] using table.transpose i a b
def graphTable (table : Table n d) : GraphTables.Table :=
⟨n, n * d, flatRows table, flatRows_valid table⟩
def tableWords (table : Table n d) : List Nat := GraphTables.tableWords (graphTable table)
def tableBits (table : Table n d) : List Bool := GraphTables.tableBits (graphTable table)
abbrev Input (ports : Nat) := (vertices : Nat) × Table vertices ports
def inputBits {ports : Nat} (input : Input ports) : List Bool := tableBits input.2
theorem tableWords_eq (table : Table n d) :
tableWords table = [n, n * d] ++ (flatRows table).toList.flatMap GraphTables.rowWords := rfl
theorem tableWords_length (table : Table n d) :
(tableWords table).length = 2 + 4098 * (n * d) :=
GraphTables.tableWords_length (graphTable table)
theorem vertices_le_tableBits_length (table : Table n d) : n ≤ (tableBits table).length :=
GraphTables.vertices_le_tableBits_length (graphTable table)
end DFVSGames.Foundations.PCP.PortTables
section
open scoped BigOperators
namespace DFVSGames.Foundations.PCP.DegreeReplacement
open PoweringWalks
variable {V E A D : Type*}
abbrev Cloud (G : ConstraintGraph V E A) (v : V) := {e : E // G.tail e = v}
def cloudIndexEquiv (G : ConstraintGraph V E A) :
(E × D) ≃ (Σ v : V, Cloud G v × D) where
toFun p := ⟨G.tail p.1, (⟨p.1, rfl⟩, p.2)⟩
invFun p := (p.2.1.val, p.2.2)
left_inv _ := rfl
right_inv := by
rintro ⟨v, ⟨⟨e, he⟩, d⟩⟩
cases he
rfl
def cloudRotation (G : ConstraintGraph V E A)
(H : ∀ v, PortGraph (Cloud G v) D) :
(Σ v : V, Cloud G v × D) ≃ (Σ v : V, Cloud G v × D) :=
Equiv.sigmaCongrRight (fun v => (H v).rot)
theorem cloudRotation_involutive (G : ConstraintGraph V E A)
(H : ∀ v, PortGraph (Cloud G v) D) :
Function.Involutive (cloudRotation G H) := by
rintro ⟨v, p⟩
change (⟨v, (H v).rot ((H v).rot p)⟩ : Σ v : V, Cloud G v × D) = ⟨v, p⟩
rw [(H v).rot_involutive p]
def innerRotation (G : ConstraintGraph V E A)
(H : ∀ v, PortGraph (Cloud G v) D) : (E × D) ≃ (E × D) :=
((cloudIndexEquiv G).trans (cloudRotation G H)).trans (cloudIndexEquiv G).symm
theorem innerRotation_involutive (G : ConstraintGraph V E A)
(H : ∀ v, PortGraph (Cloud G v) D) :
Function.Involutive (innerRotation G H) := by
intro p
apply (cloudIndexEquiv G).injective
simp only [innerRotation, Equiv.trans_apply, Equiv.apply_symm_apply]
exact cloudRotation_involutive G H _
theorem innerRotation_tail (G : ConstraintGraph V E A)
(H : ∀ v, PortGraph (Cloud G v) D) (e : E) (d : D) :
G.tail (innerRotation G H (e, d)).1 = G.tail e := by
change G.tail (((H (G.tail e)).rot (⟨e, rfl⟩, d)).1.val) = G.tail e
exact ((H (G.tail e)).rot (⟨e, rfl⟩, d)).1.property
def replacementStep (G : ConstraintGraph V E A)
(H : ∀ v, PortGraph (Cloud G v) D) : E × (D ⊕ Unit) → E × (D ⊕ Unit)
| (e, Sum.inl d) =>
let p := innerRotation G H (e, d)
(p.1, Sum.inl p.2)
| (e, Sum.inr u) => (G.reverse e, Sum.inr u)
theorem replacementStep_involutive (G : ConstraintGraph V E A)
(H : ∀ v, PortGraph (Cloud G v) D) :
Function.Involutive (replacementStep G H) := by
rintro ⟨e, p⟩
rcases p with d | u
· change ((innerRotation G H (innerRotation G H (e, d))).1,
(Sum.inl ((innerRotation G H (innerRotation G H (e, d))).2) : D ⊕ Unit)) =
(e, Sum.inl d)
rw [innerRotation_involutive G H (e, d)]
· change (G.reverse (G.reverse e), (Sum.inr u : D ⊕ Unit)) = (e, Sum.inr u)
rw [G.reverse_involutive e]
def replacementPortGraph (G : ConstraintGraph V E A)
(H : ∀ v, PortGraph (Cloud G v) D) : PortGraph E (D ⊕ Unit) where
rot :=
{ toFun := replacementStep G H
invFun := replacementStep G H
left_inv := replacementStep_involutive G H
right_inv := replacementStep_involutive G H }
rot_involutive := replacementStep_involutive G H
def replacementGraph [DecidableEq A] (G : ConstraintGraph V E A)
(H : ∀ v, PortGraph (Cloud G v) D) :
ConstraintGraph E (E × (D ⊕ Unit)) A where
reverse := (replacementPortGraph G H).rot
reverse_involutive := (replacementPortGraph G H).rot_involutive
tail := Prod.fst
accepts p a b := match p.2 with
| Sum.inl _ => decide (a = b)
| Sum.inr _ => G.accepts p.1 a b
reverse_accepts := by
rintro ⟨e, p⟩ a b
rcases p with d | u
· change decide (b = a) = decide (a = b)
simp [eq_comm]
· exact G.reverse_accepts e a b
def liftLabel (G : ConstraintGraph V E A) (labeling : V → A) : E → A :=
fun e => labeling (G.tail e)
@[simp] theorem replacement_satisfied_inl [DecidableEq A]
(G : ConstraintGraph V E A) (H : ∀ v, PortGraph (Cloud G v) D)
(labeling : V → A) (e : E) (d : D) :
(replacementGraph G H).edgeSatisfied (liftLabel G labeling) (e, Sum.inl d) =
true := by
change decide (labeling (G.tail e) =
labeling (G.tail (innerRotation G H (e, d)).1)) = true
rw [innerRotation_tail G H e d]
simp
@[simp] theorem replacement_satisfied_inr [DecidableEq A]
(G : ConstraintGraph V E A) (H : ∀ v, PortGraph (Cloud G v) D)
(labeling : V → A) (e : E) (u : Unit) :
(replacementGraph G H).edgeSatisfied (liftLabel G labeling) (e, Sum.inr u) =
G.edgeSatisfied labeling e := rfl
theorem replacement_complete [DecidableEq A]
(G : ConstraintGraph V E A) (H : ∀ v, PortGraph (Cloud G v) D)
(labeling : V → A) (h : ∀ e, G.edgeSatisfied labeling e = true) :
∀ p, (replacementGraph G H).edgeSatisfied (liftLabel G labeling) p = true := by
rintro ⟨e, p⟩
rcases p with d | u
· exact replacement_satisfied_inl G H labeling e d
· rw [replacement_satisfied_inr]
exact h e
theorem replacement_satisfiable [DecidableEq A]
(G : ConstraintGraph V E A) (H : ∀ v, PortGraph (Cloud G v) D)
(h : G.Satisfiable) : (replacementGraph G H).Satisfiable := by
obtain ⟨labeling, hlabeling⟩ := h
exact ⟨liftLabel G labeling, replacement_complete G H labeling hlabeling⟩
theorem rejectionCount_eq_sum [Fintype E] (G : ConstraintGraph V E A)
(labeling : V → A) :
G.rejectionCount labeling =
∑ e, if G.edgeSatisfied labeling e = false then 1 else 0 := by
classical
simp only [ConstraintGraph.rejectionCount, ConstraintGraph.rejectedDarts,
Finset.card_eq_sum_ones, Finset.sum_filter]
theorem replacement_rejectionCount [Fintype E] [Fintype D] [DecidableEq A]
(G : ConstraintGraph V E A) (H : ∀ v, PortGraph (Cloud G v) D)
(labeling : V → A) :
(replacementGraph G H).rejectionCount (liftLabel G labeling) =
G.rejectionCount labeling := by
classical
simp only [rejectionCount_eq_sum, Fintype.sum_prod_type, Fintype.sum_sum_type]
simp
simp only [Finset.card_filter]
congr 1
abbrev PaddedDart (_G : ConstraintGraph V E A) (dummy : V → Type*) :=
E ⊕ (Σ v : V, dummy v)
def paddedOwner (G : ConstraintGraph V E A) (dummy : V → Type*) :
PaddedDart G dummy → V
| Sum.inl e => G.tail e
| Sum.inr z => z.1
def paddedReverse (G : ConstraintGraph V E A) (dummy : V → Type*) :
PaddedDart G dummy ≃ PaddedDart G dummy :=
Equiv.sumCongr G.reverse (Equiv.refl (Σ v : V, dummy v))
theorem paddedReverse_involutive (G : ConstraintGraph V E A) (dummy : V → Type*) :
Function.Involutive (paddedReverse G dummy) := by
intro z
cases z with
| inl e =>
change (Sum.inl (G.reverse (G.reverse e)) : PaddedDart G dummy) = Sum.inl e
rw [G.reverse_involutive e]
| inr z => rfl
def paddedGraph (G : ConstraintGraph V E A) (dummy : V → Type*) :
ConstraintGraph V (PaddedDart G dummy) A where
reverse := paddedReverse G dummy
reverse_involutive := paddedReverse_involutive G dummy
tail := paddedOwner G dummy
accepts e a b := match e with
| Sum.inl e => G.accepts e a b
| Sum.inr _ => true
reverse_accepts := by
intro e a b
cases e with
| inl e => exact G.reverse_accepts e a b
| inr z => rfl
@[simp] theorem padded_satisfied_inl (G : ConstraintGraph V E A)
(dummy : V → Type*) (labeling : V → A) (e : E) :
(paddedGraph G dummy).edgeSatisfied labeling (Sum.inl e) =
G.edgeSatisfied labeling e := rfl
@[simp] theorem padded_satisfied_inr (G : ConstraintGraph V E A)
(dummy : V → Type*) (labeling : V → A) (z : Σ v : V, dummy v) :
(paddedGraph G dummy).edgeSatisfied labeling (Sum.inr z) = true := rfl
theorem padded_complete (G : ConstraintGraph V E A) (dummy : V → Type*)
(labeling : V → A) (h : ∀ e, G.edgeSatisfied labeling e = true) :
∀ c, (paddedGraph G dummy).edgeSatisfied labeling c = true := by
intro c
cases c with
| inl e => exact h e
| inr z => rfl
theorem padded_satisfiable (G : ConstraintGraph V E A) (dummy : V → Type*)
(h : G.Satisfiable) : (paddedGraph G dummy).Satisfiable := by
obtain ⟨labeling, hlabeling⟩ := h
exact ⟨labeling, padded_complete G dummy labeling hlabeling⟩
theorem card_paddedDart [Fintype V] [Fintype E] (G : ConstraintGraph V E A)
(dummy : V → Type*) [∀ v, Fintype (dummy v)] :
Fintype.card (PaddedDart G dummy) =
Fintype.card E + ∑ v, Fintype.card (dummy v) := by
rw [Fintype.card_sum, Fintype.card_sigma]
theorem padded_rejectionCount [Fintype V] [Fintype E]
(G : ConstraintGraph V E A) (dummy : V → Type*) [∀ v, Fintype (dummy v)]
(labeling : V → A) :
(paddedGraph G dummy).rejectionCount labeling = G.rejectionCount labeling := by
classical
simp only [rejectionCount_eq_sum, Fintype.sum_sum_type]
simp
simp only [Finset.card_filter]
congr 1
def paddedReplacementPortGraph (G : ConstraintGraph V E A) (dummy : V → Type*)
(H : ∀ v, PortGraph (Cloud (paddedGraph G dummy) v) D) :
PortGraph (PaddedDart G dummy) (D ⊕ Unit) :=
replacementPortGraph (paddedGraph G dummy) H
def paddedReplacementGraph [DecidableEq A]
(G : ConstraintGraph V E A) (dummy : V → Type*)
(H : ∀ v, PortGraph (Cloud (paddedGraph G dummy) v) D) :
ConstraintGraph (PaddedDart G dummy) (PaddedDart G dummy × (D ⊕ Unit)) A :=
replacementGraph (paddedGraph G dummy) H
theorem paddedReplacement_rejectionCount
[Fintype V] [Fintype E] [Fintype D] [DecidableEq A]
(G : ConstraintGraph V E A) (dummy : V → Type*) [∀ v, Fintype (dummy v)]
(H : ∀ v, PortGraph (Cloud (paddedGraph G dummy) v) D) (labeling : V → A) :
(paddedReplacementGraph G dummy H).rejectionCount
(liftLabel (paddedGraph G dummy) labeling) = G.rejectionCount labeling :=
(replacement_rejectionCount (paddedGraph G dummy) H labeling).trans
(padded_rejectionCount G dummy labeling)
def noDummyEquiv (G : ConstraintGraph V E A) :
PaddedDart G (fun _ : V => Empty) ≃ E where
toFun z := match z with
| Sum.inl e => e
| Sum.inr z => Empty.elim z.2
invFun := Sum.inl
left_inv := by
intro z
cases z with
| inl e => rfl
| inr z => exact Empty.elim z.2
right_inv _ := rfl
end DFVSGames.Foundations.PCP.DegreeReplacement
end
noncomputable section
namespace DFVSGames.Foundations.PCP.AssignmentTester
open DFVSGames.Foundations.Hastad
open scoped BigOperators
open Finset
variable {A : Type*} [Fintype A] [DecidableEq A]
def truth (b : Bool) : ℝ := if b then 1 else 0
def disagree (a b : Bool) : ℝ := if a = b then 0 else 1
theorem truth_nonneg (b : Bool) : 0 ≤ truth b := by cases b <;> norm_num [truth]
theorem disagree_nonneg (a b : Bool) : 0 ≤ disagree a b := by
cases a <;> cases b <;> norm_num [disagree]
theorem disagree_eq (a b : Bool) :
disagree a b = (1 - bitSign a * bitSign b) / 2 := by
cases a <;> cases b <;> norm_num [disagree, bitSign]
theorem disagree_xor_le (a b c d : Bool) :
disagree (a ^^ b) (c ^^ d) ≤ disagree a c + disagree b d := by
cases a <;> cases b <;> cases c <;> cases d <;> norm_num [disagree]
def parity (s f : Cube A) : Bool :=
decide (Odd ((Finset.univ.filter fun a => s a && f a = true).card))
theorem bitSign_parity (s f : Cube A) : bitSign (parity s f) = walsh s f := by
have hw : walsh s f = (-1 : ℝ) ^
(Finset.univ.filter fun a => s a && f a = true).card := by
simp [walsh, bitSign, Finset.prod_ite]
rw [hw]
simpa [parity, bitSign] using
(sign_power_parity true (Finset.univ.filter fun a => s a && f a = true).card).symm
theorem bitSign_injective : Function.Injective bitSign := by
intro a b h
cases a <;> cases b <;> simp_all [bitSign] <;> linarith
theorem parity_xor (s f g : Cube A) :
parity s (cubeXor f g) = (parity s f ^^ parity s g) := by
apply bitSign_injective
rw [bitSign_parity, bitSign_xor, bitSign_parity, bitSign_parity, walsh_xor]
omit [Fintype A] [DecidableEq A] in
theorem cubeXor_comm (f g : Cube A) : cubeXor f g = cubeXor g f := by
funext a
simp [cubeXor, Bool.xor_comm]
omit [Fintype A] [DecidableEq A] in
@[simp] theorem cubeXor_right_twice (f g : Cube A) :
cubeXor (cubeXor f g) g = f := by
funext a
change ((f a ^^ g a) ^^ g a) = f a
cases f a <;> cases g a <;> rfl
theorem expect_cubeXor (F : Cube A → ℝ) (g : Cube A) :
(𝔼 f, F (cubeXor f g)) = 𝔼 f, F f := by
rw [Fintype.expect_eq_sum_div_card, Fintype.expect_eq_sum_div_card]
congr 1
refine Finset.sum_bij (fun f _ => cubeXor f g) ?_ ?_ ?_ ?_
· intro f _
exact Finset.mem_univ _
· intro f _ h _ heq
have hh := congrArg (fun x => cubeXor x g) heq
simpa only [cubeXor_right_twice] using hh
· intro f _
exact ⟨cubeXor f g, Finset.mem_univ _, cubeXor_right_twice f g⟩
· intro f _
rfl
def distance {K : Type*} [Fintype K] (f g : K → Bool) : ℝ :=
𝔼 k, disagree (f k) (g k)
theorem distance_nonneg {K : Type*} [Fintype K] (f g : K → Bool) :
0 ≤ distance f g := by
apply Finset.expect_nonneg
intro k _
exact disagree_nonneg _ _
theorem distance_parity (F : Cube A → Bool) (s : Cube A) :
distance F (parity s) = (1 - coefficient (fun f => bitSign (F f)) s) / 2 := by
unfold distance
simp_rw [disagree_eq, bitSign_parity, div_eq_mul_inv,
← Finset.expect_mul, Finset.expect_sub_distrib]
simp only [Fintype.expect_const]
rfl
def blrReject (F : Cube A → Bool) : ℝ :=
𝔼 f, 𝔼 g, disagree (F f ^^ F g) (F (cubeXor f g))
theorem blrReject_nonneg (F : Cube A → Bool) : 0 ≤ blrReject F := by
apply Finset.expect_nonneg
intro f _
apply Finset.expect_nonneg
intro g _
exact disagree_nonneg _ _
theorem blr_correlation (F : Cube A → Bool) :
(𝔼 f, 𝔼 g, bitSign (F f) * bitSign (F g) * bitSign (F (cubeXor f g))) =
∑ s, coefficient (fun f => bitSign (F f)) s ^ 3 := by
simp_rw [mul_assoc, ← Finset.mul_expect]
conv_lhs =>
enter [2, f, 2, 2, g, 2, 1]
rw [cubeXor_comm]
simp_rw [walsh_autocorrelation, Finset.mul_sum]
rw [Finset.expect_sum_comm]
apply Finset.sum_congr rfl
intro s _
have heq (f : Cube A) : bitSign (F f) *
(coefficient (fun f => bitSign (F f)) s ^ 2 * walsh s f) =
coefficient (fun f => bitSign (F f)) s ^ 2 * (bitSign (F f) * walsh s f) := by ring
simp_rw [heq, ← Finset.mul_expect]
change coefficient (fun f => bitSign (F f)) s ^ 2 *
coefficient (fun f => bitSign (F f)) s = _
ring
theorem blrReject_fourier (F : Cube A → Bool) :
blrReject F = (1 - ∑ s, coefficient (fun f => bitSign (F f)) s ^ 3) / 2 := by
unfold blrReject
simp_rw [disagree_eq, bitSign_xor, div_eq_mul_inv,
← Finset.expect_mul, Finset.expect_sub_distrib]
simp only [Fintype.expect_const]
rw [blr_correlation]
theorem blr_near_parity (F : Cube A → Bool) :
∃ s : Cube A, distance F (parity s) ≤ blrReject F := by
classical
let c := coefficient (fun f => bitSign (F f))
have hmass : (∑ s, c s ^ 2) = 1 := sign_parseval F
have hlarge : ∃ s, (∑ t, c t ^ 3) ≤ c s := by
by_contra hn
push Not at hn
have hpos : ∃ s, 0 < c s ^ 2 := by
by_contra hh
push Not at hh
have hz := Finset.sum_nonpos (s := Finset.univ) (fun s _ => hh s)
linarith
obtain ⟨s₀, hs₀⟩ := hpos
have hle (s : Cube A) (_ : s ∈ Finset.univ) :
c s ^ 3 ≤ (∑ t, c t ^ 3) * c s ^ 2 := by
have h := mul_le_mul_of_nonneg_right (hn s).le (sq_nonneg (c s))
nlinarith
have hlt : c s₀ ^ 3 < (∑ t, c t ^ 3) * c s₀ ^ 2 := by
have h := mul_lt_mul_of_pos_right (hn s₀) hs₀
nlinarith
have hsum := Finset.sum_lt_sum hle ⟨s₀, Finset.mem_univ _, hlt⟩
rw [← Finset.mul_sum, hmass, mul_one] at hsum
exact (lt_irrefl _ hsum)
obtain ⟨s, hs⟩ := hlarge
refine ⟨s, ?_⟩
rw [distance_parity, blrReject_fourier]
dsimp [c] at hs
linarith
def selfCorrect (F : Cube A → Bool) (x r : Cube A) : Bool :=
F r ^^ F (cubeXor r x)
theorem parity_selfCorrect (s x r : Cube A) :
(parity s r ^^ parity s (cubeXor r x)) = parity s x := by
rw [parity_xor]
cases parity s r <;> cases parity s x <;> rfl
theorem selfCorrect_error (F : Cube A → Bool) (s x : Cube A) :
(𝔼 r, disagree (selfCorrect F x r) (parity s x)) ≤ 2 * distance F (parity s) := by
have hle (r : Cube A) :
disagree (selfCorrect F x r) (parity s x) ≤
disagree (F r) (parity s r) +
disagree (F (cubeXor r x)) (parity s (cubeXor r x)) := by
rw [← parity_selfCorrect s x r]
exact disagree_xor_le _ _ _ _
have h := Finset.expect_le_expect (s := Finset.univ) (fun r _ => hle r)
rw [Finset.expect_add_distrib,
expect_cubeXor (fun r => disagree (F r) (parity s r)) x] at h
change _ ≤ distance F (parity s) + distance F (parity s) at h
linarith
def singleMask (i : A) : Cube A := fun j => decide (j = i)
def flipAt (i : A) (f : Cube A) : Cube A :=
fun j => if j = i then !(f j) else f j
omit [Fintype A] in
@[simp] theorem flipAt_twice (i : A) (f : Cube A) : flipAt i (flipAt i f) = f := by
funext j
by_cases h : j = i <;> simp [flipAt, h]
omit [Fintype A] in
theorem flipAt_eq_xor (i : A) (f : Cube A) : flipAt i f = cubeXor f (singleMask i) := by
funext j
by_cases h : j = i <;> simp [flipAt, cubeXor, singleMask, h]
theorem expect_flipAt (F : Cube A → ℝ) (i : A) :
(𝔼 f, F (flipAt i f)) = 𝔼 f, F f := by
simp_rw [flipAt_eq_xor]
exact expect_cubeXor F _
theorem walsh_singleMask (s : Cube A) (i : A) :
walsh s (singleMask i) = bitSign (s i) := by
unfold walsh
rw [Finset.prod_eq_single i]
· simp [singleMask]
· intro j _ hj
simp [singleMask, hj, bitSign]
· intro h
exact False.elim (h (Finset.mem_univ _))
theorem parity_singleMask (s : Cube A) (i : A) : parity s (singleMask i) = s i := by
apply bitSign_injective
rw [bitSign_parity, walsh_singleMask]
theorem parity_flipAt (s : Cube A) (i : A) (f : Cube A) (hs : s i = true) :
parity s (flipAt i f) = !(parity s f) := by
rw [flipAt_eq_xor, parity_xor, parity_singleMask, hs]
cases parity s f <;> rfl
def cubeAnd (f g : Cube A) : Cube A := fun a => f a && g a
def andLawFailure (s f g : Cube A) : Bool :=
parity s (cubeAnd f g) ^^ (parity s f && parity s g)
theorem andLawFailure_flipAt_second (s : Cube A) (i : A) (f g : Cube A)
(hi : s i = true) :
andLawFailure s f (flipAt i g) =
(andLawFailure s f g ^^ (parity s f ^^ f i)) := by
have hAnd : cubeAnd f (flipAt i g) =
(if f i then flipAt i (cubeAnd f g) else cubeAnd f g) := by
funext a
by_cases ha : a = i
· subst a
cases hfi : f i <;> simp [cubeAnd, flipAt, hfi]
· cases hfi : f i <;> simp [cubeAnd, flipAt, ha]
have hg := parity_flipAt s i g hi
have hfg := parity_flipAt s i (cubeAnd f g) hi
cases hfi : f i <;> cases hf : parity s f <;>
cases hg₀ : parity s g <;> cases ha : parity s (cubeAnd f g) <;>
simp [andLawFailure, hAnd, hg, hfg, hfi, hf, hg₀, ha]
private theorem four_truth_lower_inline_AssignmentTester (e₀ e₁ d : Bool) :
(1 : ℝ) ≤ truth e₀ + truth (e₀ ^^ d) + truth e₁ + truth (e₁ ^^ (!d)) := by
cases e₀ <;> cases e₁ <;> cases d <;> norm_num [truth]
theorem parity_and_rejection (s : Cube A) (i j : A)
(hi : s i = true) (hj : s j = true) (hij : i ≠ j) :
(1 : ℝ) / 4 ≤ 𝔼 f, 𝔼 g, truth (andLawFailure s f g) := by
have hpoint (f g : Cube A) : (1 : ℝ) ≤
truth (andLawFailure s f g) + truth (andLawFailure s f (flipAt i g)) +
truth (andLawFailure s (flipAt j f) g) +
truth (andLawFailure s (flipAt j f) (flipAt i g)) := by
rw [andLawFailure_flipAt_second s i f g hi,
andLawFailure_flipAt_second s i (flipAt j f) g hi]
have hD : (parity s (flipAt j f) ^^ (flipAt j f) i) =
!(parity s f ^^ f i) := by
rw [parity_flipAt s j f hj]
simp only [flipAt, ite_eq_right hij]
cases hf : parity s f <;> cases hfi : f i <;> simp []
rw [hD]
exact four_truth_lower_inline_AssignmentTester _ _ _
have havg := Finset.expect_le_expect (s := Finset.univ) (fun f _ =>
Finset.expect_le_expect (s := Finset.univ) (fun g _ => hpoint f g))
simp only [Finset.expect_add_distrib, Fintype.expect_const] at havg
have hinner (f : Cube A) :
(𝔼 g, truth (andLawFailure s f (flipAt i g))) =
𝔼 g, truth (andLawFailure s f g) :=
expect_flipAt (fun g => truth (andLawFailure s f g)) i
have houter : (𝔼 f, 𝔼 g, truth (andLawFailure s (flipAt j f) g)) =
𝔼 f, 𝔼 g, truth (andLawFailure s f g) :=
expect_flipAt (fun f => 𝔼 g, truth (andLawFailure s f g)) j
simp only [hinner, houter] at havg
linarith
theorem truth_xor (a b : Bool) : truth (a ^^ b) = disagree a b := by
cases a <;> cases b <;> norm_num [truth, disagree]
theorem disagree_triangle (a b c : Bool) :
disagree a c ≤ disagree a b + disagree b c := by
cases a <;> cases b <;> cases c <;> norm_num [disagree]
theorem and_disagree_transfer (p₀ p₁ p₂ q₀ q₁ q₂ : Bool) :
disagree p₀ (p₁ && p₂) ≤ disagree q₀ (q₁ && q₂) +
disagree q₀ p₀ + disagree q₁ p₁ + disagree q₂ p₂ := by
cases p₀ <;> cases p₁ <;> cases p₂ <;>
cases q₀ <;> cases q₁ <;> cases q₂ <;> norm_num [disagree]
def andReject (F : Cube A → Bool) : ℝ :=
𝔼 f, 𝔼 g, 𝔼 r₀, 𝔼 r₁, 𝔼 r₂,
disagree (selfCorrect F (cubeAnd f g) r₀)
(selfCorrect F f r₁ && selfCorrect F g r₂)
def unitReject (F : Cube A → Bool) : ℝ :=
𝔼 r, disagree (selfCorrect F (fun _ => true) r) true
variable {K : Type*} [Fintype K] [Nonempty K]
def inputReject (label : A → K → Bool) (σ : K → Bool) (F : Cube A → Bool) : ℝ :=
𝔼 k, 𝔼 r, disagree (σ k) (selfCorrect F (fun a => label a k) r)
def testerReject (label : A → K → Bool) (σ : K → Bool) (F : Cube A → Bool) : ℝ :=
(blrReject F + andReject F + unitReject F + inputReject label σ F) / 4
theorem andReject_nonneg (F : Cube A → Bool) : 0 ≤ andReject F := by
apply Finset.expect_nonneg
intro f _
apply Finset.expect_nonneg
intro g _
apply Finset.expect_nonneg
intro r₀ _
apply Finset.expect_nonneg
intro r₁ _
apply Finset.expect_nonneg
intro r₂ _
exact disagree_nonneg _ _
theorem unitReject_nonneg (F : Cube A → Bool) : 0 ≤ unitReject F := by
apply Finset.expect_nonneg
intro r _
exact disagree_nonneg _ _
omit [Nonempty K] in
theorem inputReject_nonneg (label : A → K → Bool) (σ : K → Bool) (F : Cube A → Bool) :
0 ≤ inputReject label σ F := by
apply Finset.expect_nonneg
intro k _
apply Finset.expect_nonneg
intro r _
exact disagree_nonneg _ _
theorem andReject_transfer (F : Cube A → Bool) (s : Cube A) :
(𝔼 f, 𝔼 g, truth (andLawFailure s f g)) ≤
andReject F + 6 * distance F (parity s) := by
have hlocal (f g : Cube A) : truth (andLawFailure s f g) ≤
(𝔼 r₀, 𝔼 r₁, 𝔼 r₂,
disagree (selfCorrect F (cubeAnd f g) r₀)
(selfCorrect F f r₁ && selfCorrect F g r₂)) +
6 * distance F (parity s) := by
have hp (r₀ r₁ r₂ : Cube A) := and_disagree_transfer
(parity s (cubeAnd f g)) (parity s f) (parity s g)
(selfCorrect F (cubeAnd f g) r₀) (selfCorrect F f r₁) (selfCorrect F g r₂)
have havg := Finset.expect_le_expect (s := Finset.univ) (fun r₀ _ =>
Finset.expect_le_expect (s := Finset.univ) (fun r₁ _ =>
Finset.expect_le_expect (s := Finset.univ) (fun r₂ _ => hp r₀ r₁ r₂)))
simp only [Finset.expect_add_distrib, Fintype.expect_const] at havg
have h₀ := selfCorrect_error F s (cubeAnd f g)
have h₁ := selfCorrect_error F s f
have h₂ := selfCorrect_error F s g
rw [andLawFailure, truth_xor]
linarith
have h := Finset.expect_le_expect (s := Finset.univ) (fun f _ =>
Finset.expect_le_expect (s := Finset.univ) (fun g _ => hlocal f g))
simpa only [Finset.expect_add_distrib, Fintype.expect_const, andReject] using h
theorem parity_zero (f : Cube A) : parity (fun _ => false) f = false := by
apply bitSign_injective
rw [bitSign_parity]
simp [walsh, bitSign]
theorem unitReject_zero_parity (F : Cube A → Bool) :
1 - 2 * distance F (parity (fun _ => false)) ≤ unitReject F := by
have herr := selfCorrect_error F (fun _ => false) (fun _ => true)
simp only [parity_zero] at herr
have heq : unitReject F +
(𝔼 r, disagree (selfCorrect F (fun _ => true) r) false) = 1 := by
unfold unitReject
rw [← Finset.expect_add_distrib]
have hp (b : Bool) : disagree b true + disagree b false = 1 := by
cases b <;> norm_num [disagree]
simp only [hp, Fintype.expect_const]
linarith
theorem parity_singleMask_eval (a : A) (f : Cube A) :
parity (singleMask a) f = f a := by
apply bitSign_injective
rw [bitSign_parity, walsh_symm, walsh_singleMask]
theorem inputReject_transfer (label : A → K → Bool) (σ : K → Bool)
(F : Cube A → Bool) (a : A) :
distance σ (label a) ≤ inputReject label σ F +
2 * distance F (parity (singleMask a)) := by
have hlocal (k : K) : disagree (σ k) (label a k) ≤
(𝔼 r, disagree (σ k) (selfCorrect F (fun a => label a k) r)) +
2 * distance F (parity (singleMask a)) := by
have hp (r : Cube A) := disagree_triangle (σ k)
(selfCorrect F (fun a => label a k) r) (label a k)
have havg := Finset.expect_le_expect (s := Finset.univ) (fun r _ => hp r)
simp only [Fintype.expect_const, Finset.expect_add_distrib] at havg
have herr := selfCorrect_error F (singleMask a) (fun a => label a k)
simp only [parity_singleMask_eval] at herr
linarith
have h := Finset.expect_le_expect (s := Finset.univ) (fun k _ => hlocal k)
simpa only [Finset.expect_add_distrib, Fintype.expect_const, inputReject, distance] using h
theorem tester_proximity_soundness (label : A → K → Bool) (σ : K → Bool)
(F : Cube A → Bool) {δ : ℝ} (hδ : 0 < δ) (hδ' : δ ≤ 1 / 4)
(hfar : ∀ a, δ ≤ distance σ (label a)) :
δ / 256 ≤ testerReject label σ F := by
have hblr := blrReject_nonneg F
have hand := andReject_nonneg F
have hunit := unitReject_nonneg F
have hin := inputReject_nonneg label σ F
by_cases hb : δ / 64 ≤ blrReject F
· unfold testerReject
linarith
obtain ⟨s, hs⟩ := blr_near_parity F
by_cases hz : s = fun _ => false
· subst s
have hu := unitReject_zero_parity F
unfold testerReject
linarith
have hsome : ∃ i, s i = true := by
by_contra hh
push Not at hh
apply hz
funext i
have h := hh i
cases hi : s i <;> simp_all
obtain ⟨i, hi⟩ := hsome
by_cases htwo : ∃ j, i ≠ j ∧ s j = true
· obtain ⟨j, hij, hj⟩ := htwo
have ha := parity_and_rejection s i j hi hj hij
have ht := andReject_transfer F s
unfold testerReject
linarith
· have heq : s = singleMask i := by
funext j
by_cases hji : j = i
· subst j
simp [singleMask, hi]
· have hj : s j = false := by
cases hv : s j
· rfl
· exact False.elim (htwo ⟨j, Ne.symm hji, hv⟩)
simp [singleMask, hji, hj]
subst s
have ht := inputReject_transfer label σ F i
have hf := hfar i
unfold testerReject
linarith
omit [Fintype A] [DecidableEq A] in
theorem selfCorrect_dictator (a : A) (x r : Cube A) :
selfCorrect (fun f => f a) x r = x a := by
change (r a ^^ (r a ^^ x a)) = x a
cases r a <;> cases x a <;> rfl
omit [Nonempty K] in
theorem tester_perfect_completeness (label : A → K → Bool) (a : A) :
testerReject label (label a) (fun f => f a) = 0 := by
have hb : blrReject (fun f : Cube A => f a) = 0 := by
simp [blrReject, cubeXor, disagree]
have ha : andReject (fun f : Cube A => f a) = 0 := by
simp [andReject, selfCorrect_dictator, cubeAnd, disagree]
have hu : unitReject (fun f : Cube A => f a) = 0 := by
simp [unitReject, selfCorrect_dictator, disagree]
have hi : inputReject label (label a) (fun f => f a) = 0 := by
simp [inputReject, selfCorrect_dictator, disagree]
simp [testerReject, hb, ha, hu, hi]
def eventQueries (label : A → K → Bool) (kind : Fin 4) (k : K)
(f g r₀ r₁ r₂ : Cube A) (slot : Fin 6) : K ⊕ Cube A :=
if kind = 0 then
if slot = 0 then .inr f else if slot = 1 then .inr g else .inr (cubeXor f g)
else if kind = 1 then
if slot = 0 then .inr r₀ else
if slot = 1 then .inr (cubeXor r₀ (cubeAnd f g)) else
if slot = 2 then .inr r₁ else
if slot = 3 then .inr (cubeXor r₁ f) else
if slot = 4 then .inr r₂ else .inr (cubeXor r₂ g)
else if kind = 2 then
if slot = 0 then .inr r₀ else .inr (cubeXor r₀ (fun _ => true))
else
if slot = 0 then .inl k else
if slot = 1 then .inr r₀ else .inr (cubeXor r₀ (fun a => label a k))
def eventAccepts (kind : Fin 4) (b : Fin 6 → Bool) : Bool :=
if kind = 0 then decide ((b 0 ^^ b 1) = b 2)
else if kind = 1 then decide ((b 0 ^^ b 1) = ((b 2 ^^ b 3) && (b 4 ^^ b 5)))
else if kind = 2 then (b 0 ^^ b 1)
else decide (b 0 = (b 1 ^^ b 2))
def oracleAnswer (σ : K → Bool) (F : Cube A → Bool) : K ⊕ Cube A → Bool :=
Sum.elim σ F
def eventReject (label : A → K → Bool) (σ : K → Bool) (F : Cube A → Bool)
(kind : Fin 4) (k : K) (f g r₀ r₁ r₂ : Cube A) : ℝ :=
truth (!(eventAccepts kind (fun slot =>
oracleAnswer σ F (eventQueries label kind k f g r₀ r₁ r₂ slot))))
theorem truth_not_decide_eq (a b : Bool) : truth (!(decide (a = b))) = disagree a b := by
cases a <;> cases b <;> norm_num [truth, disagree]
omit [Fintype A] [DecidableEq A] [Fintype K] [Nonempty K] in
theorem eventReject_blr (label : A → K → Bool) (σ : K → Bool) (F : Cube A → Bool)
(k : K) (f g r₀ r₁ r₂ : Cube A) :
eventReject label σ F 0 k f g r₀ r₁ r₂ =
disagree (F f ^^ F g) (F (cubeXor f g)) := by
simp [eventReject, eventAccepts, eventQueries, oracleAnswer, truth_not_decide_eq]
omit [Fintype A] [DecidableEq A] [Fintype K] [Nonempty K] in
theorem eventReject_and (label : A → K → Bool) (σ : K → Bool) (F : Cube A → Bool)
(k : K) (f g r₀ r₁ r₂ : Cube A) :
eventReject label σ F 1 k f g r₀ r₁ r₂ =
disagree (selfCorrect F (cubeAnd f g) r₀)
(selfCorrect F f r₁ && selfCorrect F g r₂) := by
simp [eventReject, eventAccepts, eventQueries, oracleAnswer,
truth_not_decide_eq, selfCorrect]
omit [Fintype A] [DecidableEq A] [Fintype K] [Nonempty K] in
theorem eventReject_unit (label : A → K → Bool) (σ : K → Bool) (F : Cube A → Bool)
(k : K) (f g r₀ r₁ r₂ : Cube A) :
eventReject label σ F 2 k f g r₀ r₁ r₂ =
disagree (selfCorrect F (fun _ => true) r₀) true := by
simp only [eventReject, eventAccepts, eventQueries, oracleAnswer]
norm_num
change truth (!(selfCorrect F (fun _ => true) r₀)) =
disagree (selfCorrect F (fun _ => true) r₀) true
cases selfCorrect F (fun _ => true) r₀ <;> norm_num [truth, disagree]
omit [Fintype A] [DecidableEq A] [Fintype K] [Nonempty K] in
theorem eventReject_input (label : A → K → Bool) (σ : K → Bool) (F : Cube A → Bool)
(k : K) (f g r₀ r₁ r₂ : Cube A) :
eventReject label σ F 3 k f g r₀ r₁ r₂ =
disagree (σ k) (selfCorrect F (fun a => label a k) r₀) := by
simp [eventReject, eventAccepts, eventQueries, oracleAnswer,
truth_not_decide_eq, selfCorrect]
omit [Fintype A] [DecidableEq A] [Fintype K] [Nonempty K] in
theorem event_perfect_completeness (label : A → K → Bool) (a : A)
(kind : Fin 4) (k : K) (f g r₀ r₁ r₂ : Cube A) :
eventAccepts kind (fun slot => oracleAnswer (label a) (fun x => x a)
(eventQueries label kind k f g r₀ r₁ r₂ slot)) = true := by
have hkind : kind = 0 ∨ kind = 1 ∨ kind = 2 ∨ kind = 3 := by omega
have hreject : eventReject label (label a) (fun x => x a) kind k f g r₀ r₁ r₂ = 0 := by
rcases hkind with h | h | h | h <;> subst kind
· simp [eventReject_blr, cubeXor, disagree]
· simp [eventReject_and, selfCorrect_dictator, cubeAnd, disagree]
· simp [eventReject_unit, selfCorrect_dictator, disagree]
· simp [eventReject_input, selfCorrect_dictator, disagree]
unfold eventReject at hreject
cases h : eventAccepts kind (fun slot => oracleAnswer (label a) (fun x => x a)
(eventQueries label kind k f g r₀ r₁ r₂ slot)) <;> simp_all [truth]
def explicitTesterReject (label : A → K → Bool) (σ : K → Bool) (F : Cube A → Bool) : ℝ :=
𝔼 kind : Fin 4, 𝔼 k, 𝔼 f, 𝔼 g, 𝔼 r₀, 𝔼 r₁, 𝔼 r₂,
eventReject label σ F kind k f g r₀ r₁ r₂
theorem explicitTesterReject_eq (label : A → K → Bool) (σ : K → Bool)
(F : Cube A → Bool) : explicitTesterReject label σ F = testerReject label σ F := by
unfold explicitTesterReject
rw [Fintype.expect_eq_sum_div_card]
simp [Fin.sum_univ_succ, eventReject_blr, eventReject_and, eventReject_unit,
eventReject_input, testerReject, blrReject, andReject, unitReject, inputReject, add_assoc]
theorem explicit_proximity_soundness (label : A → K → Bool) (σ : K → Bool)
(F : Cube A → Bool) {δ : ℝ} (hδ : 0 < δ) (hδ' : δ ≤ 1 / 4)
(hfar : ∀ a, δ ≤ distance σ (label a)) :
δ / 256 ≤ explicitTesterReject label σ F := by
rw [explicitTesterReject_eq]
exact tester_proximity_soundness label σ F hδ hδ' hfar
end DFVSGames.Foundations.PCP.AssignmentTester
end
end OAI