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-rw-r--r--Data/Circuit/Convert.agda181
-rw-r--r--Data/Circuit/Gate.agda137
-rw-r--r--Data/Circuit/Merge.agda427
-rw-r--r--Data/Circuit/Typecheck.agda78
-rw-r--r--Data/Circuit/Value.agda180
5 files changed, 1003 insertions, 0 deletions
diff --git a/Data/Circuit/Convert.agda b/Data/Circuit/Convert.agda
new file mode 100644
index 0000000..d5abd35
--- /dev/null
+++ b/Data/Circuit/Convert.agda
@@ -0,0 +1,181 @@
+{-# OPTIONS --without-K --safe #-}
+
+module Data.Circuit.Convert where
+
+open import Level using (0ℓ)
+
+import Data.Vec as Vec
+import Data.Vec.Relation.Binary.Equality.Cast as VecCast
+import Data.List.Relation.Binary.Permutation.Propositional as L
+import Data.Vec.Functional.Relation.Binary.Permutation as V
+import DecorationFunctor.Hypergraph.Labeled {0ℓ} {0ℓ} as LabeledHypergraph
+
+open import Data.Nat.Base using (ℕ)
+open import Data.Circuit.Gate using (Gate; Gates; cast-gate; cast-gate-is-id; subst-is-cast-gate)
+open import Data.Circuit {0ℓ} {0ℓ} using (Circuit; Circuitₛ; _≈_; mkCircuit; module Edge; mk≈)
+open import Data.Fin.Base using (Fin)
+open import Data.Product.Base using (_,_)
+open import Data.Permutation using (fromList-↭; toList-↭)
+open import Data.List using (length)
+open import Data.Vec.Functional using (toVec; fromVec; toList; fromList)
+open import Function.Bundles using (Equivalence; _↔_)
+open import Function.Base using (_∘_; id)
+open import Data.Vec.Properties using (tabulate-cong; tabulate-∘; map-cast)
+open import Data.Fin.Base using () renaming (cast to fincast)
+open import Data.Fin.Properties using () renaming (cast-trans to fincast-trans; cast-is-id to fincast-is-id)
+open import Data.List.Relation.Binary.Permutation.Homogeneous using (Permutation)
+open import Data.Product.Base using (proj₁; proj₂; _×_)
+open import Data.Fin.Permutation using (flip; _⟨$⟩ˡ_)
+open import Relation.Binary.PropositionalEquality as ≡ using (_≡_; _≗_)
+
+open LabeledHypergraph using (Hypergraph-same) renaming (Hypergraph to Hypergraph′; Hypergraph-setoid to Hypergraph-Setoid′)
+
+to : {v : ℕ} → Circuit v → Hypergraph′ v
+to C = record
+ { h = length edges
+ ; a = arity ∘ fromList edges
+ ; j = fromVec ∘ ports ∘ fromList edges
+ ; l = label ∘ fromList edges
+ }
+ where
+ open Edge.Edge using (arity; ports; label)
+ open Circuit C
+
+from : {v : ℕ} → Hypergraph′ v → Circuit v
+from {v} H = record
+ { edges = toList asEdge
+ }
+ where
+ open Hypergraph′ H
+ asEdge : Fin h → Edge.Edge v
+ asEdge e = record { label = l e ; ports = toVec (j e) }
+
+to-cong : {v : ℕ} {H H′ : Circuit v} → H ≈ H′ → Hypergraph-same (to H) (to H′)
+to-cong {v} {H} {H′} ≈H = record
+ { ↔h = flip ρ
+ ; ≗a = ≗a
+ ; ≗j = ≗j
+ ; ≗l = ≗l
+ }
+ where
+ open Edge.Edge using (arity; ports; label)
+ open _≈_ ≈H
+ open import Data.Fin.Permutation using (_⟨$⟩ʳ_; _⟨$⟩ˡ_; Permutation′; inverseʳ)
+ open import Data.Fin.Base using (cast)
+ open import Data.Fin.Properties using (cast-is-id)
+ ρ : Fin (length H′.edges) ↔ Fin (length H.edges)
+ ρ = proj₁ (fromList-↭ ↭-edges)
+
+ open ≡.≡-Reasoning
+ edges≗ρ∘edges′ : (i : Fin (length H.edges)) → fromList H.edges i ≡ fromList H′.edges (ρ ⟨$⟩ˡ i)
+ edges≗ρ∘edges′ i = begin
+ fromList H.edges i ≡⟨ ≡.cong (fromList H.edges) (inverseʳ ρ) ⟨
+ fromList H.edges (ρ ⟨$⟩ʳ (ρ ⟨$⟩ˡ i)) ≡⟨ proj₂ (fromList-↭ ↭-edges) (ρ ⟨$⟩ˡ i) ⟩
+ fromList H′.edges (ρ ⟨$⟩ˡ i) ∎
+
+ ≗a : (e : Fin (Hypergraph′.h (to H)))
+ → Hypergraph′.a (to H) e
+ ≡ arity (fromList H′.edges (ρ ⟨$⟩ˡ e))
+ ≗a = ≡.cong arity ∘ edges≗ρ∘edges′
+
+ ≗j : (e : Fin (Hypergraph′.h (to H)))
+ (i : Fin (Hypergraph′.a (to H) e))
+ → fromVec (ports (fromList H.edges e)) i
+ ≡ fromVec (ports (fromList H′.edges (ρ ⟨$⟩ˡ e))) (cast (≗a e) i)
+ ≗j e i
+ rewrite edges≗ρ∘edges′ e
+ rewrite cast-is-id ≡.refl i = ≡.refl
+
+ ≗l : (e : Fin (Hypergraph′.h (to H)))
+ → label (fromList H.edges e)
+ ≡ cast-gate (≡.sym (≗a e)) (label (fromList H′.edges (ρ ⟨$⟩ˡ e)))
+ ≗l e
+ rewrite edges≗ρ∘edges′ e
+ rewrite cast-gate-is-id ≡.refl (label (fromList H′.edges (ρ ⟨$⟩ˡ e))) =
+ ≡.refl
+
+module _ {v : ℕ} where
+ open import Data.Hypergraph.Label using (HypergraphLabel)
+ open HypergraphLabel Gates using (isCastable)
+ open import Data.Castable using (IsCastable)
+ open IsCastable isCastable using (≈-reflexive; ≈-sym; ≈-trans)
+ from-cong
+ : {H H′ : Hypergraph′ v}
+ → Hypergraph-same H H′
+ → from H ≈ from H′
+ from-cong {H} {H′} ≈H = mk≈ (toList-↭ (flip ↔h , H∘ρ≗H′))
+ where
+
+ module H = Hypergraph′ H
+ module H′ = Hypergraph′ H′
+ open Hypergraph′
+ open Hypergraph-same ≈H using (↔h; ≗a; ≗l; ≗j; inverseˡ) renaming (from to f; to to t)
+ asEdge : (H : Hypergraph′ v) → Fin (h H) → Edge.Edge v
+ asEdge H e = record { label = l H e ; ports = toVec (j H e) }
+
+ to-from : (e : Fin H′.h) → t (f e) ≡ e
+ to-from e = inverseˡ ≡.refl
+
+ a∘to-from : (e : Fin H′.h) → H′.a (t (f e)) ≡ H′.a e
+ a∘to-from = ≡.cong H′.a ∘ to-from
+
+ ≗a′ : (e : Fin H′.h) → H.a (f e) ≡ H′.a e
+ ≗a′ e = ≡.trans (≗a (f e)) (a∘to-from e)
+
+ l≗ : (e : Fin H.h) → cast-gate (≗a e) (H.l e) ≡ H′.l (t e)
+ l≗ e = ≈-sym (≡.sym (≗l e))
+
+ l∘to-from : (e : Fin H′.h) → cast-gate (a∘to-from e) (H′.l (t (f e))) ≡ H′.l e
+ l∘to-from e rewrite to-from e = ≈-reflexive ≡.refl
+
+ ≗l′ : (e : Fin H′.h) → cast-gate (≗a′ e) (H.l (f e)) ≡ H′.l e
+ ≗l′ e = ≈-trans {H.a _} (l≗ (f e)) (l∘to-from e)
+
+ j∘to-from
+ : (e : Fin H′.h) (i : Fin (H′.a (t (f e))))
+ → H′.j (t (f e)) i
+ ≡ H′.j e (fincast (a∘to-from e) i)
+ j∘to-from e i rewrite to-from e = ≡.cong (H′.j e) (≡.sym (fincast-is-id ≡.refl i))
+
+ open ≡.≡-Reasoning
+
+ ≗j′ : (e : Fin H′.h) (i : Fin (H.a (f e))) → H.j (f e) i ≡ H′.j e (fincast (≗a′ e) i)
+ ≗j′ e i = begin
+ H.j (f e) i ≡⟨ ≗j (f e) i ⟩
+ H′.j (t (f e)) (fincast _ i) ≡⟨ j∘to-from e (fincast _ i) ⟩
+ H′.j e (fincast (a∘to-from e) (fincast _ i)) ≡⟨ ≡.cong (H′.j e) (fincast-trans (≗a (f e)) _ i) ⟩
+ H′.j e (fincast (≗a′ e) i) ∎
+
+ cast-toVec
+ : {n m : ℕ}
+ {A : Set}
+ (m≡n : m ≡ n)
+ (f : Fin n → A)
+ → Vec.cast m≡n (toVec (f ∘ fincast m≡n)) ≡ toVec f
+ cast-toVec m≡n f rewrite m≡n = begin
+ Vec.cast _ (toVec (f ∘ (fincast _))) ≡⟨ VecCast.cast-is-id ≡.refl (toVec (f ∘ fincast ≡.refl)) ⟩
+ toVec (f ∘ fincast _) ≡⟨ tabulate-∘ f (fincast ≡.refl) ⟩
+ Vec.map f (toVec (fincast _)) ≡⟨ ≡.cong (Vec.map f) (tabulate-cong (fincast-is-id ≡.refl)) ⟩
+ Vec.map f (toVec id) ≡⟨ tabulate-∘ f id ⟨
+ toVec f ∎
+
+ ≗p′ : (e : Fin H′.h) → Vec.cast (≗a′ e) (toVec (H.j (f e))) ≡ toVec (H′.j e)
+ ≗p′ e = begin
+ Vec.cast (≗a′ e) (toVec (H.j (f e))) ≡⟨ ≡.cong (Vec.cast (≗a′ e)) (tabulate-cong (≗j′ e)) ⟩
+ Vec.cast _ (toVec (H′.j e ∘ fincast _)) ≡⟨ cast-toVec (≗a′ e) (H′.j e) ⟩
+ toVec (H′.j e) ∎
+
+ H∘ρ≗H′ : (e : Fin H′.h) → asEdge H (↔h ⟨$⟩ˡ e) ≡ asEdge H′ e
+ H∘ρ≗H′ e = Edge.≈⇒≡ record
+ { ≡arity = ≗a′ e
+ ; ≡label = ≗l′ e
+ ; ≡ports = ≗p′ e
+ }
+
+equiv : (v : ℕ) → Equivalence (Circuitₛ v) (Hypergraph-Setoid′ v)
+equiv v = record
+ { to = to
+ ; from = from
+ ; to-cong = to-cong
+ ; from-cong = from-cong
+ }
diff --git a/Data/Circuit/Gate.agda b/Data/Circuit/Gate.agda
new file mode 100644
index 0000000..f4b55de
--- /dev/null
+++ b/Data/Circuit/Gate.agda
@@ -0,0 +1,137 @@
+{-# OPTIONS --without-K --safe #-}
+
+module Data.Circuit.Gate where
+
+open import Level using (0ℓ)
+open import Data.Castable using (Castable)
+open import Data.Hypergraph.Label using (HypergraphLabel)
+open import Data.String using (String)
+open import Data.Nat.Base using (ℕ; _≤_)
+open import Data.Nat.Properties using (≤-refl; ≤-trans; ≤-antisym; ≤-total)
+open import Relation.Binary.PropositionalEquality using (_≡_; refl; sym; trans; subst; isEquivalence; cong)
+import Relation.Binary.PropositionalEquality as ≡
+
+import Data.Nat as Nat
+import Data.Fin as Fin
+
+data Gate : ℕ → Set where
+ ZERO : Gate 1
+ ONE : Gate 1
+ ID : Gate 2
+ NOT : Gate 2
+ AND : Gate 3
+ OR : Gate 3
+ XOR : Gate 3
+ NAND : Gate 3
+ NOR : Gate 3
+ XNOR : Gate 3
+
+cast-gate : {e e′ : ℕ} → .(e ≡ e′) → Gate e → Gate e′
+cast-gate {1} {1} eq g = g
+cast-gate {2} {2} eq g = g
+cast-gate {3} {3} eq g = g
+
+cast-gate-trans
+ : {m n o : ℕ}
+ → .(eq₁ : m ≡ n)
+ .(eq₂ : n ≡ o)
+ (g : Gate m)
+ → cast-gate eq₂ (cast-gate eq₁ g) ≡ cast-gate (trans eq₁ eq₂) g
+cast-gate-trans {1} {1} {1} eq₁ eq₂ g = refl
+cast-gate-trans {2} {2} {2} eq₁ eq₂ g = refl
+cast-gate-trans {3} {3} {3} eq₁ eq₂ g = refl
+
+cast-gate-is-id : {m : ℕ} .(eq : m ≡ m) (g : Gate m) → cast-gate eq g ≡ g
+cast-gate-is-id {1} eq g = refl
+cast-gate-is-id {2} eq g = refl
+cast-gate-is-id {3} eq g = refl
+
+subst-is-cast-gate : {m n : ℕ} (eq : m ≡ n) (g : Gate m) → subst Gate eq g ≡ cast-gate eq g
+subst-is-cast-gate refl g = sym (cast-gate-is-id refl g)
+
+GateCastable : Castable
+GateCastable = record
+ { B = Gate
+ ; isCastable = record
+ { cast = cast-gate
+ ; cast-trans = cast-gate-trans
+ ; cast-is-id = cast-gate-is-id
+ ; subst-is-cast = subst-is-cast-gate
+ }
+ }
+
+showGate : (n : ℕ) → Gate n → String
+showGate _ ZERO = "ZERO"
+showGate _ ONE = "ONE"
+showGate _ ID = "ID"
+showGate _ NOT = "NOT"
+showGate _ AND = "AND"
+showGate _ OR = "OR"
+showGate _ XOR = "XOR"
+showGate _ NAND = "NAND"
+showGate _ NOR = "NOR"
+showGate _ XNOR = "XNOR"
+
+toℕ : (n : ℕ) → Gate n → ℕ
+toℕ 1 ZERO = 0
+toℕ 1 ONE = 1
+toℕ 2 ID = 0
+toℕ 2 NOT = 1
+toℕ 3 AND = 0
+toℕ 3 OR = 1
+toℕ 3 XOR = 2
+toℕ 3 NAND = 3
+toℕ 3 NOR = 4
+toℕ 3 XNOR = 5
+
+toℕ-injective : {n : ℕ} {x y : Gate n} → toℕ n x ≡ toℕ n y → x ≡ y
+toℕ-injective {1} {ZERO} {ZERO} refl = refl
+toℕ-injective {1} {ONE} {ONE} refl = refl
+toℕ-injective {2} {ID} {ID} refl = refl
+toℕ-injective {2} {NOT} {NOT} refl = refl
+toℕ-injective {3} {AND} {AND} refl = refl
+toℕ-injective {3} {OR} {OR} refl = refl
+toℕ-injective {3} {XOR} {XOR} refl = refl
+toℕ-injective {3} {NAND} {NAND} refl = refl
+toℕ-injective {3} {NOR} {NOR} refl = refl
+toℕ-injective {3} {XNOR} {XNOR} refl = refl
+
+open import Relation.Binary using (Rel; Decidable; DecidableEquality)
+import Relation.Nullary.Decidable as Dec
+
+_[_≤_] : (n : ℕ) → Rel (Gate n) 0ℓ
+_[_≤_] n x y = toℕ n x ≤ toℕ n y
+
+_≟_ : {n : ℕ} → DecidableEquality (Gate n)
+_≟_ {n} x y = Dec.map′ toℕ-injective (cong (toℕ n)) (toℕ n x Nat.≟ toℕ n y)
+
+_≤?_ : {n : ℕ} → Decidable (n [_≤_])
+_≤?_ {n} x y = toℕ n x Nat.≤? toℕ n y
+
+Gates : HypergraphLabel
+Gates = record
+ { Label = Gate
+ ; showLabel = showGate
+ ; isCastable = record
+ { cast = cast-gate
+ ; cast-trans = cast-gate-trans
+ ; cast-is-id = cast-gate-is-id
+ ; subst-is-cast = subst-is-cast-gate
+ }
+ ; _[_≤_] = λ n x y → toℕ n x ≤ toℕ n y
+ ; isDecTotalOrder = λ n → record
+ { isTotalOrder = record
+ { isPartialOrder = record
+ { isPreorder = record
+ { isEquivalence = isEquivalence
+ ; reflexive = λ { refl → ≤-refl }
+ ; trans = ≤-trans
+ }
+ ; antisym = λ i≤j j≤i → toℕ-injective (≤-antisym i≤j j≤i)
+ }
+ ; total = λ { x y → ≤-total (toℕ n x) (toℕ n y) }
+ }
+ ; _≟_ = _≟_
+ ; _≤?_ = _≤?_
+ }
+ }
diff --git a/Data/Circuit/Merge.agda b/Data/Circuit/Merge.agda
new file mode 100644
index 0000000..9cf180a
--- /dev/null
+++ b/Data/Circuit/Merge.agda
@@ -0,0 +1,427 @@
+{-# OPTIONS --without-K --safe #-}
+
+module Data.Circuit.Merge where
+
+open import Data.Nat.Base using (ℕ)
+open import Data.Fin.Base using (Fin; pinch; punchIn; punchOut; splitAt)
+open import Data.Fin.Properties using (punchInᵢ≢i; punchIn-punchOut)
+open import Data.Bool.Properties using (if-eta)
+open import Data.Bool using (Bool; if_then_else_)
+open import Data.Circuit.Value using (Value; join; join-comm; join-assoc)
+open import Data.Sum.Properties using ([,]-cong; [,-]-cong; [-,]-cong; [,]-∘; [,]-map)
+open import Data.Subset.Functional
+ using
+ ( Subset
+ ; ⁅_⁆ ; ⊥ ; ⁅⁆∘ρ
+ ; foldl ; foldl-cong₁ ; foldl-cong₂
+ ; foldl-[] ; foldl-suc
+ ; foldl-⊥ ; foldl-⁅⁆
+ ; foldl-fusion
+ )
+open import Data.Vector as V using (Vector; head; tail; removeAt)
+open import Data.Vec.Functional using (_++_)
+open import Data.Fin.Permutation
+ using
+ ( Permutation
+ ; Permutation′
+ ; _⟨$⟩ˡ_ ; _⟨$⟩ʳ_
+ ; inverseˡ ; inverseʳ
+ ; id
+ ; flip
+ ; insert ; remove
+ ; punchIn-permute
+ )
+open import Data.Product using (Σ-syntax; _,_)
+open import Data.Fin.Preimage using (preimage; preimage-cong₁; preimage-cong₂)
+open import Function.Base using (∣_⟩-_; _∘_; case_of_; _$_)
+open import Relation.Binary.PropositionalEquality as ≡ using (_≡_; _≢_; _≗_; module ≡-Reasoning)
+
+open Value using (U)
+open ℕ
+open Fin
+open Bool
+
+open ≡-Reasoning
+
+_when_ : Value → Bool → Value
+x when b = if b then x else U
+
+opaque
+ merge-with : {A : ℕ} → Value → Vector Value A → Subset A → Value
+ merge-with e v = foldl (∣ join ⟩- v) e
+
+ merge-with-cong : {A : ℕ} {v₁ v₂ : Vector Value A} (e : Value) → v₁ ≗ v₂ → merge-with e v₁ ≗ merge-with e v₂
+ merge-with-cong e v₁≗v₂ = foldl-cong₁ (λ x → ≡.cong (join x) ∘ v₁≗v₂) e
+
+ merge-with-cong₂ : {A : ℕ} (e : Value) (v : Vector Value A) {S₁ S₂ : Subset A} → S₁ ≗ S₂ → merge-with e v S₁ ≡ merge-with e v S₂
+ merge-with-cong₂ e v = foldl-cong₂ (∣ join ⟩- v) e
+
+ merge-with-⊥ : {A : ℕ} (e : Value) (v : Vector Value A) → merge-with e v ⊥ ≡ e
+ merge-with-⊥ e v = foldl-⊥ (∣ join ⟩- v) e
+
+ merge-with-[] : (e : Value) (v : Vector Value 0) (S : Subset 0) → merge-with e v S ≡ e
+ merge-with-[] e v = foldl-[] (∣ join ⟩- v) e
+
+ merge-with-suc
+ : {A : ℕ} (e : Value) (v : Vector Value (suc A)) (S : Subset (suc A))
+ → merge-with e v S
+ ≡ merge-with (if head S then join e (head v) else e) (tail v) (tail S)
+ merge-with-suc e v = foldl-suc (∣ join ⟩- v) e
+
+ merge-with-join
+ : {A : ℕ}
+ (x y : Value)
+ (v : Vector Value A)
+ → merge-with (join x y) v ≗ join x ∘ merge-with y v
+ merge-with-join {A} x y v S = ≡.sym (foldl-fusion (join x) fuse y S)
+ where
+ fuse : (acc : Value) (k : Fin A) → join x (join acc (v k)) ≡ join (join x acc) (v k)
+ fuse acc k = ≡.sym (join-assoc x acc (v k))
+
+ merge-with-⁅⁆ : {A : ℕ} (e : Value) (v : Vector Value A) (x : Fin A) → merge-with e v ⁅ x ⁆ ≡ join e (v x)
+ merge-with-⁅⁆ e v = foldl-⁅⁆ (∣ join ⟩- v) e
+
+merge-with-U : {A : ℕ} (e : Value) (S : Subset A) → merge-with e (λ _ → U) S ≡ e
+merge-with-U {zero} e S = merge-with-[] e (λ _ → U) S
+merge-with-U {suc A} e S = begin
+ merge-with e (λ _ → U) S ≡⟨ merge-with-suc e (λ _ → U) S ⟩
+ merge-with
+ (if head S then join e U else e)
+ (tail (λ _ → U)) (tail S) ≡⟨ ≡.cong (λ h → merge-with (if head S then h else e) _ _) (join-comm e U) ⟩
+ merge-with
+ (if head S then e else e)
+ (tail (λ _ → U)) (tail S) ≡⟨ ≡.cong (λ h → merge-with h (λ _ → U) (tail S)) (if-eta (head S)) ⟩
+ merge-with e (tail (λ _ → U)) (tail S) ≡⟨⟩
+ merge-with e (λ _ → U) (tail S) ≡⟨ merge-with-U e (tail S) ⟩
+ e ∎
+
+merge : {A : ℕ} → Vector Value A → Subset A → Value
+merge v = merge-with U v
+
+merge-cong₁ : {A : ℕ} {v₁ v₂ : Vector Value A} → v₁ ≗ v₂ → merge v₁ ≗ merge v₂
+merge-cong₁ = merge-with-cong U
+
+merge-cong₂ : {A : ℕ} (v : Vector Value A) {S₁ S₂ : Subset A} → S₁ ≗ S₂ → merge v S₁ ≡ merge v S₂
+merge-cong₂ = merge-with-cong₂ U
+
+merge-⊥ : {A : ℕ} (v : Vector Value A) → merge v ⊥ ≡ U
+merge-⊥ = merge-with-⊥ U
+
+merge-[] : (v : Vector Value 0) (S : Subset 0) → merge v S ≡ U
+merge-[] = merge-with-[] U
+
+merge-[]₂ : {v₁ v₂ : Vector Value 0} {S₁ S₂ : Subset 0} → merge v₁ S₁ ≡ merge v₂ S₂
+merge-[]₂ {v₁} {v₂} {S₁} {S₂} = ≡.trans (merge-[] v₁ S₁) (≡.sym (merge-[] v₂ S₂))
+
+merge-⁅⁆ : {A : ℕ} (v : Vector Value A) (x : Fin A) → merge v ⁅ x ⁆ ≡ v x
+merge-⁅⁆ = merge-with-⁅⁆ U
+
+join-merge : {A : ℕ} (e : Value) (v : Vector Value A) (S : Subset A) → join e (merge v S) ≡ merge-with e v S
+join-merge e v S = ≡.sym (≡.trans (≡.cong (λ h → merge-with h v S) (join-comm U e)) (merge-with-join e U v S))
+
+merge-suc
+ : {A : ℕ} (v : Vector Value (suc A)) (S : Subset (suc A))
+ → merge v S
+ ≡ merge-with (head v when head S) (tail v) (tail S)
+merge-suc = merge-with-suc U
+
+insert-f0-0
+ : {A B : ℕ}
+ (f : Fin (suc A) → Fin (suc B))
+ → Σ[ ρ ∈ Permutation′ (suc B) ] (ρ ⟨$⟩ʳ (f zero) ≡ zero)
+insert-f0-0 f = insert (f zero) zero id , help
+ where
+ open import Data.Fin using (_≟_)
+ open import Relation.Nullary.Decidable using (yes; no)
+ help : insert (f zero) zero id ⟨$⟩ʳ f zero ≡ zero
+ help with f zero ≟ f zero
+ ... | yes _ = ≡.refl
+ ... | no f0≢f0 with () ← f0≢f0 ≡.refl
+
+merge-removeAt
+ : {A : ℕ}
+ (k : Fin (suc A))
+ (v : Vector Value (suc A))
+ (S : Subset (suc A))
+ → merge v S ≡ join (v k when S k) (merge (removeAt v k) (removeAt S k))
+merge-removeAt {A} zero v S = begin
+ merge-with U v S ≡⟨ merge-suc v S ⟩
+ merge-with (head v when head S) (tail v) (tail S) ≡⟨ join-merge (head v when head S) (tail v) (tail S) ⟨
+ join (head v when head S) (merge-with U (tail v) (tail S)) ∎
+merge-removeAt {suc A} (suc k) v S = begin
+ merge-with U v S ≡⟨ merge-suc v S ⟩
+ merge-with v0? (tail v) (tail S) ≡⟨ join-merge _ (tail v) (tail S) ⟨
+ join v0? (merge (tail v) (tail S)) ≡⟨ ≡.cong (join v0?) (merge-removeAt k (tail v) (tail S)) ⟩
+ join v0? (join vk? (merge (tail v-) (tail S-))) ≡⟨ join-assoc (head v when head S) _ _ ⟨
+ join (join v0? vk?) (merge (tail v-) (tail S-)) ≡⟨ ≡.cong (λ h → join h (merge (tail v-) (tail S-))) (join-comm (head v- when head S-) _) ⟩
+ join (join vk? v0?) (merge (tail v-) (tail S-)) ≡⟨ join-assoc (tail v k when tail S k) _ _ ⟩
+ join vk? (join v0? (merge (tail v-) (tail S-))) ≡⟨ ≡.cong (join vk?) (join-merge _ (tail v-) (tail S-)) ⟩
+ join vk? (merge-with v0? (tail v-) (tail S-)) ≡⟨ ≡.cong (join vk?) (merge-suc v- S-) ⟨
+ join vk? (merge v- S-) ∎
+ where
+ v0? vk? : Value
+ v0? = head v when head S
+ vk? = tail v k when tail S k
+ v- : Vector Value (suc A)
+ v- = removeAt v (suc k)
+ S- : Subset (suc A)
+ S- = removeAt S (suc k)
+
+import Function.Structures as FunctionStructures
+open module FStruct {A B : Set} = FunctionStructures {_} {_} {_} {_} {A} _≡_ {B} _≡_ using (IsInverse)
+open IsInverse using () renaming (inverseˡ to invˡ; inverseʳ to invʳ)
+
+merge-preimage-ρ
+ : {A B : ℕ}
+ → (ρ : Permutation A B)
+ → (v : Vector Value A)
+ (S : Subset B)
+ → merge v (preimage (ρ ⟨$⟩ʳ_) S) ≡ merge (v ∘ (ρ ⟨$⟩ˡ_)) S
+merge-preimage-ρ {zero} {zero} ρ v S = merge-[]₂
+merge-preimage-ρ {zero} {suc B} ρ v S with () ← ρ ⟨$⟩ˡ zero
+merge-preimage-ρ {suc A} {zero} ρ v S with () ← ρ ⟨$⟩ʳ zero
+merge-preimage-ρ {suc A} {suc B} ρ v S = begin
+ merge v (preimage ρʳ S) ≡⟨ merge-removeAt (head ρˡ) v (preimage ρʳ S) ⟩
+ join
+ (head (v ∘ ρˡ) when S (ρʳ (ρˡ zero)))
+ (merge v- [preimageρʳS]-) ≡⟨ ≡.cong (λ h → join h (merge v- [preimageρʳS]-)) ≡vρˡ0? ⟩
+ join vρˡ0? (merge v- [preimageρʳS]-) ≡⟨ ≡.cong (join vρˡ0?) (merge-cong₂ v- preimage-) ⟩
+ join vρˡ0? (merge v- (preimage ρʳ- S-)) ≡⟨ ≡.cong (join vρˡ0?) (merge-preimage-ρ ρ- v- S-) ⟩
+ join vρˡ0? (merge (v- ∘ ρˡ-) S-) ≡⟨ ≡.cong (join vρˡ0?) (merge-cong₁ v∘ρˡ- S-) ⟩
+ join vρˡ0? (merge (tail (v ∘ ρˡ)) S-) ≡⟨ join-merge vρˡ0? (tail (v ∘ ρˡ)) S- ⟩
+ merge-with vρˡ0? (tail (v ∘ ρˡ)) S- ≡⟨ merge-suc (v ∘ ρˡ) S ⟨
+ merge (v ∘ ρˡ) S ∎
+ where
+ ρˡ : Fin (suc B) → Fin (suc A)
+ ρˡ = ρ ⟨$⟩ˡ_
+ ρʳ : Fin (suc A) → Fin (suc B)
+ ρʳ = ρ ⟨$⟩ʳ_
+ ρ- : Permutation A B
+ ρ- = remove (head ρˡ) ρ
+ ρˡ- : Fin B → Fin A
+ ρˡ- = ρ- ⟨$⟩ˡ_
+ ρʳ- : Fin A → Fin B
+ ρʳ- = ρ- ⟨$⟩ʳ_
+ v- : Vector Value A
+ v- = removeAt v (head ρˡ)
+ [preimageρʳS]- : Subset A
+ [preimageρʳS]- = removeAt (preimage ρʳ S) (head ρˡ)
+ S- : Subset B
+ S- = tail S
+ vρˡ0? : Value
+ vρˡ0? = head (v ∘ ρˡ) when head S
+ ≡vρˡ0?  : head (v ∘ ρˡ) when S (ρʳ (head ρˡ)) ≡ head (v ∘ ρˡ) when head S
+ ≡vρˡ0? = ≡.cong ((head (v ∘ ρˡ) when_) ∘ S) (inverseʳ ρ)
+ v∘ρˡ- : v- ∘ ρˡ- ≗ tail (v ∘ ρˡ)
+ v∘ρˡ- x = begin
+ v- (ρˡ- x) ≡⟨⟩
+ v (punchIn (head ρˡ) (punchOut {A} {head ρˡ} _)) ≡⟨ ≡.cong v (punchIn-punchOut _) ⟩
+ v (ρˡ (punchIn (ρʳ (ρˡ zero)) x)) ≡⟨ ≡.cong (λ h → v (ρˡ (punchIn h x))) (inverseʳ ρ) ⟩
+ v (ρˡ (punchIn zero x)) ≡⟨⟩
+ v (ρˡ (suc x)) ≡⟨⟩
+ tail (v ∘ ρˡ) x ∎
+ preimage- : [preimageρʳS]- ≗ preimage ρʳ- S-
+ preimage- x = begin
+ [preimageρʳS]- x ≡⟨⟩
+ removeAt (preimage ρʳ S) (head ρˡ) x ≡⟨⟩
+ S (ρʳ (punchIn (head ρˡ) x)) ≡⟨ ≡.cong S (punchIn-permute ρ (head ρˡ) x) ⟩ 
+ S (punchIn (ρʳ (head ρˡ)) (ρʳ- x)) ≡⟨⟩
+ S (punchIn (ρʳ (ρˡ zero)) (ρʳ- x)) ≡⟨ ≡.cong (λ h → S (punchIn h (ρʳ- x))) (inverseʳ ρ) ⟩ 
+ S (punchIn zero (ρʳ- x)) ≡⟨⟩ 
+ S (suc (ρʳ- x)) ≡⟨⟩
+ preimage ρʳ- S- x ∎
+
+push-with : {A B : ℕ} → (e : Value) → Vector Value A → (Fin A → Fin B) → Vector Value B
+push-with e v f = merge-with e v ∘ preimage f ∘ ⁅_⁆
+
+push : {A B : ℕ} → Vector Value A → (Fin A → Fin B) → Vector Value B
+push = push-with U
+
+mutual
+ merge-preimage
+ : {A B : ℕ}
+ (f : Fin A → Fin B)
+ → (v : Vector Value A)
+ (S : Subset B)
+ → merge v (preimage f S) ≡ merge (push v f) S
+ merge-preimage {zero} {zero} f v S = merge-[]₂
+ merge-preimage {zero} {suc B} f v S = begin
+ merge v (preimage f S) ≡⟨ merge-[] v (preimage f S) ⟩
+ U ≡⟨ merge-with-U U S ⟨
+ merge (λ _ → U) S ≡⟨ merge-cong₁ (λ x → ≡.sym (merge-[] v (⁅ x ⁆ ∘ f))) S ⟩
+ merge (push v f) S ∎
+ merge-preimage {suc A} {zero} f v S with () ← f zero
+ merge-preimage {suc A} {suc B} f v S with insert-f0-0 f
+ ... | ρ , ρf0≡0 = begin
+ merge v (preimage f S) ≡⟨ merge-cong₂ v (preimage-cong₁ (λ x → inverseˡ ρ {f x}) S) ⟨
+ merge v (preimage (ρˡ ∘ ρʳ ∘ f) S) ≡⟨⟩
+ merge v (preimage (ρʳ ∘ f) (preimage ρˡ S)) ≡⟨ merge-preimage-f0≡0 (ρʳ ∘ f) ρf0≡0 v (preimage ρˡ S) ⟩
+ merge (merge v ∘ preimage (ρʳ ∘ f) ∘ ⁅_⁆) (preimage ρˡ S) ≡⟨ merge-preimage-ρ (flip ρ) (merge v ∘ preimage (ρʳ ∘ f) ∘ ⁅_⁆) S ⟩
+ merge (merge v ∘ preimage (ρʳ ∘ f) ∘ ⁅_⁆ ∘ ρʳ) S ≡⟨ merge-cong₁ (merge-cong₂ v ∘ preimage-cong₂ (ρʳ ∘ f) ∘ ⁅⁆∘ρ ρ) S ⟩
+ merge (merge v ∘ preimage (ρʳ ∘ f) ∘ preimage ρˡ ∘ ⁅_⁆) S ≡⟨⟩
+ merge (merge v ∘ preimage (ρˡ ∘ ρʳ ∘ f) ∘ ⁅_⁆) S ≡⟨ merge-cong₁ (merge-cong₂ v ∘ preimage-cong₁ (λ y → inverseˡ ρ {f y}) ∘ ⁅_⁆) S ⟩
+ merge (merge v ∘ preimage f ∘ ⁅_⁆) S ∎
+ where
+ ρʳ ρˡ : Fin (ℕ.suc B) → Fin (ℕ.suc B)
+ ρʳ = ρ ⟨$⟩ʳ_
+ ρˡ = ρ ⟨$⟩ˡ_
+
+ merge-preimage-f0≡0
+ : {A B : ℕ}
+ (f : Fin (ℕ.suc A) → Fin (ℕ.suc B))
+ → f Fin.zero ≡ Fin.zero
+ → (v : Vector Value (ℕ.suc A))
+ (S : Subset (ℕ.suc B))
+ → merge v (preimage f S) ≡ merge (merge v ∘ preimage f ∘ ⁅_⁆) S
+ merge-preimage-f0≡0 {A} {B} f f0≡0 v S
+ using S0 , S- ← head S , tail S
+ using v0 , v- ← head v , tail v
+ using _ , f- ← head f , tail f
+ = begin
+ merge v f⁻¹[S] ≡⟨ merge-suc v f⁻¹[S] ⟩
+ merge-with v0? v- f⁻¹[S]- ≡⟨ join-merge v0? v- f⁻¹[S]- ⟨
+ join v0? (merge v- f⁻¹[S]-) ≡⟨ ≡.cong (join v0?) (merge-preimage f- v- S) ⟩
+ join v0? (merge f[v-] S) ≡⟨ join-merge v0? f[v-] S ⟩
+ merge-with v0? f[v-] S ≡⟨ merge-with-suc v0? f[v-] S ⟩
+ merge-with v0?+[f[v-]0?] f[v-]- S- ≡⟨ ≡.cong (λ h → merge-with h f[v-]- S-) ≡f[v]0 ⟩
+ merge-with f[v]0? f[v-]- S- ≡⟨ merge-with-cong f[v]0? ≡f[v]- S- ⟩
+ merge-with f[v]0? f[v]- S- ≡⟨ merge-suc f[v] S ⟨
+ merge f[v] S ∎
+ where
+ f⁻¹[S] : Subset (suc A)
+ f⁻¹[S] = preimage f S
+ f⁻¹[S]- : Subset A
+ f⁻¹[S]- = tail f⁻¹[S]
+ f⁻¹[S]0 : Bool
+ f⁻¹[S]0 = head f⁻¹[S]
+ f[v] : Vector Value (suc B)
+ f[v] = push v f
+ f[v]- : Vector Value B
+ f[v]- = tail f[v]
+ f[v]0 : Value
+ f[v]0 = head f[v]
+ f[v-] : Vector Value (suc B)
+ f[v-] = push v- f-
+ f[v-]- : Vector Value B
+ f[v-]- = tail f[v-]
+ f[v-]0 : Value
+ f[v-]0 = head f[v-]
+ f⁻¹⁅0⁆ : Subset (suc A)
+ f⁻¹⁅0⁆ = preimage f ⁅ zero ⁆
+ f⁻¹⁅0⁆- : Subset A
+ f⁻¹⁅0⁆- = tail f⁻¹⁅0⁆
+ v0? v0?+[f[v-]0?] f[v]0? : Value
+ v0? = v0 when f⁻¹[S]0
+ v0?+[f[v-]0?] = (if S0 then join v0? f[v-]0 else v0?)
+ f[v]0? = f[v]0 when S0
+ ≡f[v]0 : v0?+[f[v-]0?] ≡ f[v]0?
+ ≡f[v]0 rewrite f0≡0 with S0
+ ... | true = begin
+ join v0 (merge v- f⁻¹⁅0⁆-) ≡⟨ join-merge v0 v- (tail (preimage f ⁅ zero ⁆)) ⟩
+ merge-with v0 v- f⁻¹⁅0⁆- ≡⟨ ≡.cong (λ h → merge-with (v0 when ⁅ zero ⁆ h) v- f⁻¹⁅0⁆-) f0≡0 ⟨
+ merge-with v0?′ v- f⁻¹⁅0⁆- ≡⟨ merge-suc v (preimage f ⁅ zero ⁆) ⟨
+ merge v f⁻¹⁅0⁆  ∎
+ where
+ v0?′ : Value
+ v0?′ = v0 when head f⁻¹⁅0⁆
+ ... | false = ≡.refl
+ ≡f[v]- : f[v-]- ≗ f[v]-
+ ≡f[v]- x = begin
+ push v- f- (suc x) ≡⟨ ≡.cong (λ h → merge-with (v0 when ⁅ suc x ⁆ h) v- (preimage f- ⁅ suc x ⁆)) f0≡0 ⟨
+ push-with v0?′ v- f- (suc x) ≡⟨ merge-suc v (preimage f ⁅ suc x ⁆) ⟨
+ push v f (suc x) ∎
+ where
+ v0?′ : Value
+ v0?′ = v0 when head (preimage f ⁅ suc x ⁆)
+
+merge-++
+ : {n m : ℕ}
+ (xs : Vector Value n)
+ (ys : Vector Value m)
+ (S₁ : Subset n)
+ (S₂ : Subset m)
+ → merge (xs ++ ys) (S₁ ++ S₂)
+ ≡ join (merge xs S₁) (merge ys S₂)
+merge-++ {zero} {m} xs ys S₁ S₂ = begin
+ merge (xs ++ ys) (S₁ ++ S₂) ≡⟨ merge-cong₂ (xs ++ ys) (λ _ → ≡.refl) ⟩
+ merge (xs ++ ys) S₂ ≡⟨ merge-cong₁ (λ _ → ≡.refl) S₂ ⟩
+ merge ys S₂ ≡⟨ ≡.cong (λ h → join h (merge ys S₂)) (merge-[] xs S₁) ⟨
+ join (merge xs S₁) (merge ys S₂) ∎
+merge-++ {suc n} {m} xs ys S₁ S₂ = begin
+ merge (xs ++ ys) (S₁ ++ S₂) ≡⟨ merge-suc (xs ++ ys) (S₁ ++ S₂) ⟩
+ merge-with (head xs when head S₁) (tail (xs ++ ys)) (tail (S₁ ++ S₂)) ≡⟨ join-merge (head xs when head S₁) (tail (xs ++ ys)) (tail (S₁ ++ S₂)) ⟨
+ join (head xs when head S₁) (merge (tail (xs ++ ys)) (tail (S₁ ++ S₂)))
+ ≡⟨ ≡.cong (join (head xs when head S₁)) (merge-cong₁ ([,]-map ∘ splitAt n) (tail (S₁ ++ S₂))) ⟩
+ join (head xs when head S₁) (merge (tail xs ++ ys) (tail (S₁ ++ S₂)))
+ ≡⟨ ≡.cong (join (head xs when head S₁)) (merge-cong₂ (tail xs ++ ys) ([,]-map ∘ splitAt n)) ⟩
+ join (head xs when head S₁) (merge (tail xs ++ ys) (tail S₁ ++ S₂)) ≡⟨ ≡.cong (join (head xs when head S₁)) (merge-++ (tail xs) ys (tail S₁) S₂) ⟩
+ join (head xs when head S₁) (join (merge (tail xs) (tail S₁)) (merge ys S₂)) ≡⟨ join-assoc (head xs when head S₁) (merge (tail xs) (tail S₁)) _ ⟨
+ join (join (head xs when head S₁) (merge (tail xs) (tail S₁))) (merge ys S₂)
+ ≡⟨ ≡.cong (λ h → join h (merge ys S₂)) (join-merge (head xs when head S₁) (tail xs) (tail S₁)) ⟩
+ join (merge-with (head xs when head S₁) (tail xs) (tail S₁)) (merge ys S₂) ≡⟨ ≡.cong (λ h → join h (merge ys S₂)) (merge-suc xs S₁) ⟨
+ join (merge xs S₁) (merge ys S₂) ∎
+
+open import Function using (Equivalence)
+open Equivalence
+open import Data.Nat using (_+_)
+open import Data.Fin using (_↑ˡ_; _↑ʳ_; _≟_)
+open import Data.Fin.Properties using (↑ˡ-injective; ↑ʳ-injective; splitAt⁻¹-↑ˡ; splitAt-↑ˡ; splitAt⁻¹-↑ʳ; splitAt-↑ʳ)
+open import Relation.Nullary.Decidable using (does; does-⇔; dec-false)
+
+open Fin
+⁅⁆-≟ : {n : ℕ} (x y : Fin n) → ⁅ x ⁆ y ≡ does (x ≟ y)
+⁅⁆-≟ zero zero = ≡.refl
+⁅⁆-≟ zero (suc y) = ≡.refl
+⁅⁆-≟ (suc x) zero = ≡.refl
+⁅⁆-≟ (suc x) (suc y) = ⁅⁆-≟ x y
+
+open import Data.Sum using ([_,_]′; inj₁; inj₂)
+⁅⁆-++
+ : {n′ m′ : ℕ}
+ (i : Fin (n′ + m′))
+ → [ (λ x → ⁅ x ⁆ ++ ⊥) , (λ x → ⊥ ++ ⁅ x ⁆) ]′ (splitAt n′ i) ≗ ⁅ i ⁆
+⁅⁆-++ {n′} {m′} i x with splitAt n′ i in eq₁
+... | inj₁ i′ with splitAt n′ x in eq₂
+... | inj₁ x′ = begin
+ ⁅ i′ ⁆ x′ ≡⟨ ⁅⁆-≟ i′ x′ ⟩
+ does (i′ ≟ x′) ≡⟨ does-⇔ ⇔ (i′ ≟ x′) (i′ ↑ˡ m′ ≟ x′ ↑ˡ m′) ⟩
+ does (i′ ↑ˡ m′ ≟ x′ ↑ˡ m′) ≡⟨ ⁅⁆-≟ (i′ ↑ˡ m′) (x′ ↑ˡ m′) ⟨
+ ⁅ i′ ↑ˡ m′ ⁆ (x′ ↑ˡ m′) ≡⟨ ≡.cong₂ ⁅_⁆ (splitAt⁻¹-↑ˡ eq₁) (splitAt⁻¹-↑ˡ eq₂) ⟩
+ ⁅ i ⁆ x ∎
+ where
+ ⇔ : Equivalence (≡.setoid (i′ ≡ x′)) (≡.setoid (i′ ↑ˡ m′ ≡ x′ ↑ˡ m′))
+ ⇔ .to = ≡.cong (_↑ˡ m′)
+ ⇔ .from = ↑ˡ-injective m′ i′ x′
+ ⇔ .to-cong ≡.refl = ≡.refl
+ ⇔ .from-cong ≡.refl = ≡.refl
+... | inj₂ x′ = begin
+ false ≡⟨ dec-false (i′ ↑ˡ m′ ≟ n′ ↑ʳ x′) ↑ˡ≢↑ʳ ⟨
+ does (i′ ↑ˡ m′ ≟ n′ ↑ʳ x′) ≡⟨ ⁅⁆-≟ (i′ ↑ˡ m′) (n′ ↑ʳ x′) ⟨
+ ⁅ i′ ↑ˡ m′ ⁆ (n′ ↑ʳ x′) ≡⟨ ≡.cong₂ ⁅_⁆ (splitAt⁻¹-↑ˡ eq₁) (splitAt⁻¹-↑ʳ eq₂) ⟩
+ ⁅ i ⁆ x ∎
+ where
+ ↑ˡ≢↑ʳ : i′ ↑ˡ m′ ≢ n′ ↑ʳ x′
+ ↑ˡ≢↑ʳ ≡ = case ≡.trans (≡.sym (splitAt-↑ˡ n′ i′ m′)) (≡.trans (≡.cong (splitAt n′) ≡) (splitAt-↑ʳ n′ m′ x′)) of λ { () }
+⁅⁆-++ {n′} i x | inj₂ i′ with splitAt n′ x in eq₂
+⁅⁆-++ {n′} {m′} i x | inj₂ i′ | inj₁ x′ = begin
+ [ ⊥ , ⁅ i′ ⁆ ]′ (splitAt n′ x) ≡⟨ ≡.cong ([ ⊥ , ⁅ i′ ⁆ ]′) eq₂ ⟩
+ false ≡⟨ dec-false (n′ ↑ʳ i′ ≟ x′ ↑ˡ m′) ↑ʳ≢↑ˡ ⟨
+ does (n′ ↑ʳ i′ ≟ x′ ↑ˡ m′) ≡⟨ ⁅⁆-≟ (n′ ↑ʳ i′) (x′ ↑ˡ m′) ⟨
+ ⁅ n′ ↑ʳ i′ ⁆ (x′ ↑ˡ m′) ≡⟨ ≡.cong₂ ⁅_⁆ (splitAt⁻¹-↑ʳ eq₁) (splitAt⁻¹-↑ˡ eq₂) ⟩
+ ⁅ i ⁆ x ∎
+ where
+ ↑ʳ≢↑ˡ : n′ ↑ʳ i′ ≢ x′ ↑ˡ m′
+ ↑ʳ≢↑ˡ ≡ = case ≡.trans (≡.sym (splitAt-↑ʳ n′ m′ i′)) (≡.trans (≡.cong (splitAt n′) ≡) (splitAt-↑ˡ n′ x′ m′)) of λ { () }
+⁅⁆-++ {n′} i x | inj₂ i′ | inj₂ x′ = begin
+ [ ⊥ , ⁅ i′ ⁆ ]′ (splitAt n′ x) ≡⟨ ≡.cong [ ⊥ , ⁅ i′ ⁆ ]′ eq₂ ⟩
+ ⁅ i′ ⁆ x′ ≡⟨ ⁅⁆-≟ i′ x′ ⟩
+ does (i′ ≟ x′) ≡⟨ does-⇔ ⇔ (i′ ≟ x′) (n′ ↑ʳ i′ ≟ n′ ↑ʳ x′) ⟩
+ does (n′ ↑ʳ i′ ≟ n′ ↑ʳ x′) ≡⟨ ⁅⁆-≟ (n′ ↑ʳ i′) (n′ ↑ʳ x′) ⟨
+ ⁅ n′ ↑ʳ i′ ⁆ (n′ ↑ʳ x′) ≡⟨ ≡.cong₂ ⁅_⁆ (splitAt⁻¹-↑ʳ eq₁) (splitAt⁻¹-↑ʳ eq₂) ⟩
+ ⁅ i ⁆ x ∎
+ where
+ ⇔ : Equivalence (≡.setoid (i′ ≡ x′)) (≡.setoid (n′ ↑ʳ i′ ≡ n′ ↑ʳ x′))
+ ⇔ .to = ≡.cong (n′ ↑ʳ_)
+ ⇔ .from = ↑ʳ-injective n′ i′ x′
+ ⇔ .to-cong ≡.refl = ≡.refl
+ ⇔ .from-cong ≡.refl = ≡.refl
diff --git a/Data/Circuit/Typecheck.agda b/Data/Circuit/Typecheck.agda
new file mode 100644
index 0000000..e34ea44
--- /dev/null
+++ b/Data/Circuit/Typecheck.agda
@@ -0,0 +1,78 @@
+{-# OPTIONS --without-K --safe #-}
+
+module Data.Circuit.Typecheck where
+
+open import Data.SExp using (SExp)
+open import Data.Circuit.Gate using (GateLabel; Gate)
+open import Data.Hypergraph.Label using (HypergraphLabel)
+open import Data.Hypergraph.Edge GateLabel using (Edge)
+open import Data.Hypergraph.Base GateLabel using (Hypergraph)
+
+open import Data.List using (List; length) renaming (map to mapL)
+open import Data.List.Effectful using () renaming (module TraversableA to ListTraversable)
+open import Data.Maybe using (Maybe) renaming (map to mapM)
+open import Data.Nat using (ℕ; _<?_; _≟_)
+open import Data.String using (String)
+open import Data.Product using (_×_; _,_; Σ)
+open import Data.Vec using (Vec; []; _∷_; fromList) renaming (map to mapV)
+open import Data.Vec.Effectful using () renaming (module TraversableA to VecTraversable)
+open import Data.Maybe.Effectful using (applicative)
+open import Data.Fin using (Fin; #_; fromℕ<)
+open import Level using (0ℓ)
+
+import Relation.Binary.PropositionalEquality as ≡
+
+open List
+open SExp
+open Gate
+open Maybe
+
+gate : {n a : ℕ} (g : Gate a) → Vec (Fin n) a → Edge n
+gate g p = record { label = g; ports = p }
+
+typeCheckGateLabel : SExp → Maybe (Σ ℕ Gate)
+typeCheckGateLabel (Atom "one") = just (1 , ONE)
+typeCheckGateLabel (Atom "zero") = just (1 , ZERO)
+typeCheckGateLabel (Atom "not") = just (2 , NOT)
+typeCheckGateLabel (Atom "id") = just (2 , ID)
+typeCheckGateLabel (Atom "and") = just (3 , AND)
+typeCheckGateLabel (Atom "or") = just (3 , OR)
+typeCheckGateLabel (Atom "xor") = just (3 , XOR)
+typeCheckGateLabel (Atom "nand") = just (3 , NAND)
+typeCheckGateLabel (Atom "nor") = just (3 , NOR)
+typeCheckGateLabel (Atom "xnor") = just (3 , XNOR)
+typeCheckGateLabel _ = nothing
+
+open import Relation.Nullary.Decidable using (Dec; yes; no)
+open Dec
+open VecTraversable {0ℓ} applicative using () renaming (sequenceA to vecSequenceA)
+open ListTraversable {0ℓ} applicative using () renaming (sequenceA to listSequenceA)
+
+typeCheckPort : (v : ℕ) → SExp → Maybe (Fin v)
+typeCheckPort v (Nat n) with n <? v
+... | yes n<v = just (fromℕ< n<v)
+... | no _ = nothing
+typeCheckPort _ _ = nothing
+
+typeCheckPorts : (v n : ℕ) → List SExp → Maybe (Vec (Fin v) n)
+typeCheckPorts v n xs with length xs ≟ n
+... | yes ≡.refl = vecSequenceA (mapV (typeCheckPort v) (fromList xs))
+... | no _ = nothing
+
+typeCheckGate : (v : ℕ) → SExp → Maybe (Edge v)
+typeCheckGate v (SExps (labelString ∷ ports)) with typeCheckGateLabel labelString
+... | just (n , label) = mapM (gate label) (typeCheckPorts v n ports)
+... | nothing = nothing
+typeCheckGate v _ = nothing
+
+typeCheckHeader : SExp → Maybe ℕ
+typeCheckHeader (SExps (Atom "hypergraph" ∷ Nat n ∷ [])) = just n
+typeCheckHeader _ = nothing
+
+typeCheckHypergraph : SExp → Maybe (Σ ℕ Hypergraph)
+typeCheckHypergraph (SExps (x ∷ xs)) with typeCheckHeader x
+... | nothing = nothing
+... | just n with listSequenceA (mapL (typeCheckGate n) xs)
+... | just e = just (n , record { edges = e })
+... | nothing = nothing
+typeCheckHypergraph _ = nothing
diff --git a/Data/Circuit/Value.agda b/Data/Circuit/Value.agda
new file mode 100644
index 0000000..b135c35
--- /dev/null
+++ b/Data/Circuit/Value.agda
@@ -0,0 +1,180 @@
+{-# OPTIONS --without-K --safe #-}
+
+module Data.Circuit.Value where
+
+import Relation.Binary.Lattice.Properties.BoundedJoinSemilattice as LatticeProp
+
+open import Algebra.Bundles using (CommutativeMonoid)
+open import Algebra.Structures using (IsCommutativeMonoid; IsMonoid; IsSemigroup; IsMagma)
+open import Data.Product.Base using (_×_; _,_)
+open import Data.String.Base using (String)
+open import Level using (0ℓ)
+open import Relation.Binary.Lattice.Bundles using (BoundedJoinSemilattice)
+open import Relation.Binary.PropositionalEquality as ≡ using (_≡_)
+
+open CommutativeMonoid
+open IsCommutativeMonoid
+open IsMagma
+open IsMonoid
+open IsSemigroup
+
+data Value : Set where
+ U T F X : Value
+
+data ≤-Value : Value → Value → Set where
+ v≤v : {v : Value} → ≤-Value v v
+ U≤T : ≤-Value U T
+ U≤F : ≤-Value U F
+ U≤X : ≤-Value U X
+ T≤X : ≤-Value T X
+ F≤X : ≤-Value F X
+
+≤-reflexive : {x y : Value} → x ≡ y → ≤-Value x y
+≤-reflexive ≡.refl = v≤v
+
+≤-transitive : {i j k : Value} → ≤-Value i j → ≤-Value j k → ≤-Value i k
+≤-transitive v≤v y = y
+≤-transitive x v≤v = x
+≤-transitive U≤T T≤X = U≤X
+≤-transitive U≤F F≤X = U≤X
+
+≤-antisymmetric : {i j : Value} → ≤-Value i j → ≤-Value j i → i ≡ j
+≤-antisymmetric v≤v _ = ≡.refl
+
+showValue : Value → String
+showValue U = "U"
+showValue T = "T"
+showValue F = "F"
+showValue X = "X"
+
+join : Value → Value → Value
+join U y = y
+join x U = x
+join T T = T
+join T F = X
+join F T = X
+join F F = F
+join X _ = X
+join _ X = X
+
+≤-supremum
+ : (x y : Value)
+ → ≤-Value x (join x y)
+ × ≤-Value y (join x y)
+ × ((z : Value) → ≤-Value x z → ≤-Value y z → ≤-Value (join x y) z)
+≤-supremum U U = v≤v , v≤v , λ _ U≤z _ → U≤z
+≤-supremum U T = U≤T , v≤v , λ { z x≤z y≤z → y≤z }
+≤-supremum U F = U≤F , v≤v , λ { z x≤z y≤z → y≤z }
+≤-supremum U X = U≤X , v≤v , λ { z x≤z y≤z → y≤z }
+≤-supremum T U = v≤v , U≤T , λ { z x≤z y≤z → x≤z }
+≤-supremum T T = v≤v , v≤v , λ { z x≤z y≤z → x≤z }
+≤-supremum T F = T≤X , F≤X , λ { X x≤z y≤z → v≤v }
+≤-supremum T X = T≤X , v≤v , λ { z x≤z y≤z → y≤z }
+≤-supremum F U = v≤v , U≤F , λ { z x≤z y≤z → x≤z }
+≤-supremum F T = F≤X , T≤X , λ { X x≤z y≤z → v≤v }
+≤-supremum F F = v≤v , v≤v , λ { z x≤z y≤z → x≤z }
+≤-supremum F X = F≤X , v≤v , λ { z x≤z y≤z → y≤z }
+≤-supremum X U = v≤v , U≤X , λ { z x≤z y≤z → x≤z }
+≤-supremum X T = v≤v , T≤X , λ { z x≤z y≤z → x≤z }
+≤-supremum X F = v≤v , F≤X , λ { z x≤z y≤z → x≤z }
+≤-supremum X X = v≤v , v≤v , λ { z x≤z y≤z → x≤z }
+
+join-comm : (x y : Value) → join x y ≡ join y x
+join-comm U U = ≡.refl
+join-comm U T = ≡.refl
+join-comm U F = ≡.refl
+join-comm U X = ≡.refl
+join-comm T U = ≡.refl
+join-comm T T = ≡.refl
+join-comm T F = ≡.refl
+join-comm T X = ≡.refl
+join-comm F U = ≡.refl
+join-comm F T = ≡.refl
+join-comm F F = ≡.refl
+join-comm F X = ≡.refl
+join-comm X U = ≡.refl
+join-comm X T = ≡.refl
+join-comm X F = ≡.refl
+join-comm X X = ≡.refl
+
+join-assoc : (x y z : Value) → join (join x y) z ≡ join x (join y z)
+join-assoc U y z = ≡.refl
+join-assoc T U z = ≡.refl
+join-assoc T T U = ≡.refl
+join-assoc T T T = ≡.refl
+join-assoc T T F = ≡.refl
+join-assoc T T X = ≡.refl
+join-assoc T F U = ≡.refl
+join-assoc T F T = ≡.refl
+join-assoc T F F = ≡.refl
+join-assoc T F X = ≡.refl
+join-assoc T X U = ≡.refl
+join-assoc T X T = ≡.refl
+join-assoc T X F = ≡.refl
+join-assoc T X X = ≡.refl
+join-assoc F U z = ≡.refl
+join-assoc F T U = ≡.refl
+join-assoc F T T = ≡.refl
+join-assoc F T F = ≡.refl
+join-assoc F T X = ≡.refl
+join-assoc F F U = ≡.refl
+join-assoc F F T = ≡.refl
+join-assoc F F F = ≡.refl
+join-assoc F F X = ≡.refl
+join-assoc F X U = ≡.refl
+join-assoc F X T = ≡.refl
+join-assoc F X F = ≡.refl
+join-assoc F X X = ≡.refl
+join-assoc X U z = ≡.refl
+join-assoc X T U = ≡.refl
+join-assoc X T T = ≡.refl
+join-assoc X T F = ≡.refl
+join-assoc X T X = ≡.refl
+join-assoc X F U = ≡.refl
+join-assoc X F T = ≡.refl
+join-assoc X F F = ≡.refl
+join-assoc X F X = ≡.refl
+join-assoc X X U = ≡.refl
+join-assoc X X T = ≡.refl
+join-assoc X X F = ≡.refl
+join-assoc X X X = ≡.refl
+
+Lattice : BoundedJoinSemilattice 0ℓ 0ℓ 0ℓ
+Lattice = record
+ { Carrier = Value
+ ; _≈_ = _≡_
+ ; _≤_ = ≤-Value
+ ; _∨_ = join
+ ; ⊥ = U
+ ; isBoundedJoinSemilattice = record
+ { isJoinSemilattice = record
+ { isPartialOrder = record 
+ { isPreorder = record
+ { isEquivalence = ≡.isEquivalence
+ ; reflexive = ≤-reflexive
+ ; trans = ≤-transitive
+ }
+ ; antisym = ≤-antisymmetric
+ }
+ ; supremum = ≤-supremum
+ }
+ ; minimum = λ where
+ U → v≤v
+ T → U≤T
+ F → U≤F
+ X → U≤X
+ }
+ }
+
+module Lattice = BoundedJoinSemilattice Lattice
+
+Monoid : CommutativeMonoid 0ℓ 0ℓ
+Monoid .Carrier = Lattice.Carrier
+Monoid ._≈_ = Lattice._≈_
+Monoid ._∙_ = Lattice._∨_
+Monoid .ε = Lattice.⊥
+Monoid .isCommutativeMonoid .isMonoid .isSemigroup .isMagma .isEquivalence = ≡.isEquivalence
+Monoid .isCommutativeMonoid .isMonoid .isSemigroup .isMagma .∙-cong = ≡.cong₂ join
+Monoid .isCommutativeMonoid .isMonoid .isSemigroup .assoc = join-assoc
+Monoid .isCommutativeMonoid .isMonoid .identity = LatticeProp.identity Lattice
+Monoid .isCommutativeMonoid .comm = join-comm