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import OAI.Computability.PerfectCompleteness.Foundations.RecursiveSpaceEquivLemmas
import OAI.Computability.PerfectCompleteness.Foundations.ReducedDomains
namespace OAI
section
namespace PerfectCompleteness.CanonicalKeys
open ClauseSupport MixedSupport
variable {n : Nat} {Y : Type*}
inductive Side where
| left
| right
deriving DecidableEq
structure Key (n : Nat) where
side : Side
retained : List (Fin n × SlotKey)
partition : Set (Set (Fin n → ReducedValue))
noncomputable def partition (slots : Fin n → Slot) (f : Assignment slots → Y) :
Set (Set (Fin n → ReducedValue)) :=
ReducedPartition.parts (reduction slots f) f
noncomputable def key (side : Side) (slots : Fin n → Slot)
(f : Assignment slots → Y) : Key n :=
⟨side, retainedKeys slots f, partition slots f⟩
theorem constantOnFibers (slots : Fin n → Slot) (f : Assignment slots → Y) :
ReducedPartition.ConstantOnFibers (reduction slots f) f := by
intro x x' h
exact constant_on_reduction_fibers slots f h
theorem covered_iff_legal (slots : Fin n → Slot) (f : Assignment slots → Y)
(values : Fin n → ReducedValue) :
(∃ P ∈ partition slots f, values ∈ P) ↔
values ∈ ReducedDomains.legalAssignments (keyFields slots f) := by
rw [← ReducedDomains.range_reduction slots f]
exact ReducedPartition.covered_iff_mem_range (reduction slots f) f values
theorem legal_domain_projection {slots projected : Fin n → Slot}
(p : ∀ i, Projection (slots i) (projected i)) (f : Assignment projected → Y) :
ReducedDomains.legalAssignments (keyFields slots (f ∘ projectionMap p)) =
ReducedDomains.legalAssignments (keyFields projected f) := by
rw [keyFields_projection]
theorem partition_projection {slots projected : Fin n → Slot}
(p : ∀ i, Projection (slots i) (projected i)) (f : Assignment projected → Y) :
partition slots (f ∘ projectionMap p) = partition projected f := by
exact ReducedPartition.parts_eq_of_pullback
(projectionMap p) (projectionMap_surjective p)
(reduction slots (f ∘ projectionMap p)) (reduction projected f)
(f ∘ projectionMap p) f (reduction_projection p f) (fun _ => rfl)
theorem key_projection (side : Side) {slots projected : Fin n → Slot}
(p : ∀ i, Projection (slots i) (projected i)) (f : Assignment projected → Y) :
key side slots (f ∘ projectionMap p) = key side projected f := by
simp only [key, retainedKeys_projection, partition_projection]
abbrev Label (slots : Fin n → Slot) (f : Assignment slots → Y) :=
ReducedPartition.Part (reduction slots f) f
noncomputable def evaluateLabel (slots : Fin n → Slot) (f : Assignment slots → Y)
(x : Assignment slots) : Label slots f :=
ReducedPartition.label (reduction slots f) f x
noncomputable def restore (slots : Fin n → Slot) (f : Assignment slots → Y)
(P : Label slots f) : Y :=
ReducedPartition.output (reduction slots f) f P
@[simp] theorem restore_evaluateLabel (slots : Fin n → Slot)
(f : Assignment slots → Y) (x : Assignment slots) :
restore slots f (evaluateLabel slots f x) = f x :=
ReducedPartition.output_label (reduction slots f) f (constantOnFibers slots f) x
theorem restore_injective (slots : Fin n → Slot) (f : Assignment slots → Y) :
Function.Injective (restore slots f) :=
ReducedPartition.output_injective (reduction slots f) f
noncomputable def transportLabel {slots projected : Fin n → Slot}
(p : ∀ i, Projection (slots i) (projected i)) (f : Assignment projected → Y)
(P : Label slots (f ∘ projectionMap p)) : Label projected f :=
⟨P.val, by
change P.val ∈ partition projected f
rw [← partition_projection p f]
exact P.property⟩
theorem transportLabel_bijective {slots projected : Fin n → Slot}
(p : ∀ i, Projection (slots i) (projected i)) (f : Assignment projected → Y) :
Function.Bijective (transportLabel p f) := by
constructor
· intro P Q h
exact Subtype.ext (congrArg (fun R : Label projected f => R.val) h)
· intro Q
have hQ : Q.val ∈ partition slots (f ∘ projectionMap p) := by
rw [partition_projection p f]
exact Q.property
exact ⟨⟨Q.val, hQ⟩, Subtype.ext rfl⟩
theorem evaluateLabel_projection {slots projected : Fin n → Slot}
(p : ∀ i, Projection (slots i) (projected i)) (f : Assignment projected → Y)
(x : Assignment slots) :
transportLabel p f (evaluateLabel slots (f ∘ projectionMap p) x) =
evaluateLabel projected f (projectionMap p x) := by
apply Subtype.ext
exact ReducedPartition.fiber_eq_of_pullback
(projectionMap p) (projectionMap_surjective p)
(reduction slots (f ∘ projectionMap p)) (reduction projected f)
(f ∘ projectionMap p) f (reduction_projection p f) (fun _ => rfl) x
theorem restore_projection {slots projected : Fin n → Slot}
(p : ∀ i, Projection (slots i) (projected i)) (f : Assignment projected → Y)
(P : Label slots (f ∘ projectionMap p)) :
restore slots (f ∘ projectionMap p) P =
restore projected f (transportLabel p f P) := by
exact ReducedPartition.output_eq_of_shared_part
(projectionMap p) (reduction slots (f ∘ projectionMap p)) (reduction projected f)
(f ∘ projectionMap p) f (reduction_projection p f) (fun _ => rfl)
(constantOnFibers projected f) P (transportLabel p f P) rfl
end PerfectCompleteness.CanonicalKeys
end
end OAI