Updated for 981edbc

docs/Algebra/Literals.agda

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+{-# OPTIONS --without-K --safe #-}
+
+module Algebra.Literals where
+
+open import Algebra
+
+open import Agda.Builtin.FromNat
+open import Agda.Builtin.FromNeg
+open import Level
+
+variable a b : Level
+
+module Semiring-Lit (R : Semiring a b) where
+  open Semiring R
+
+  open import Data.Unit.Polymorphic
+  open import Data.Nat using (ℕ; zero; suc)
+
+  private
+    ℕ→R : ℕ → Carrier
+    ℕ→R zero    = 0#
+    ℕ→R (suc n) = 1# + ℕ→R n
+
+  instance
+    number : Number Carrier
+    number .Number.Constraint = λ _ → ⊤
+    number .fromNat           = λ n → ℕ→R n

docs/Algebra/PairOp.agda

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+{-# OPTIONS --safe #-}
+
+open import Prelude
+
+open import Algebra
+open import Data.Product.Relation.Binary.Pointwise.NonDependent
+open import Relation.Binary
+
+module Algebra.PairOp (X : Set) (ε : X) (_≈_ : Rel X zeroˡ) (_∙_ : Op₂ X) where
+
+_∙ᵖ_ : (X × X) → (X × X) → (X × X)
+(a , b) ∙ᵖ (c , d) = (a ∙ c) , (b ∙ d)
+
+_≈ᵖ_ : Rel (X × X) zeroˡ
+_≈ᵖ_ = Pointwise _≈_ _≈_
+
+pairOpIdentityˡ :
+  Algebra.LeftIdentity _≈_ ε _∙_ → Algebra.LeftIdentity _≈ᵖ_ (ε , ε) _∙ᵖ_
+pairOpIdentityˡ idˡ (a , b) = ×-refl (idˡ a) (idˡ b) {ε , ε}
+
+pairOpIdentityʳ :
+  Algebra.RightIdentity _≈_ ε _∙_ → Algebra.RightIdentity _≈ᵖ_ (ε , ε) _∙ᵖ_
+pairOpIdentityʳ idʳ (a , b) = ×-refl (idʳ a) (idʳ b) {ε , ε}
+
+pairOpIdentity : Algebra.Identity _≈_ ε _∙_ → Algebra.Identity _≈ᵖ_ (ε , ε) _∙ᵖ_
+pairOpIdentity (idˡ , idʳ) = (pairOpIdentityˡ idˡ) , (pairOpIdentityʳ idʳ)
+
+pairOpAssoc : Algebra.Associative  _≈_ _∙_ →  Algebra.Associative _≈ᵖ_ _∙ᵖ_
+pairOpAssoc assoc (a , b) (c , d) (e , f) =
+  ×-refl (assoc a c e) (assoc b d f) {ε , ε}
+
+pairOpIsMonoid : IsMonoid _≈_ _∙_ ε →  IsMonoid _≈ᵖ_ _∙ᵖ_ (ε , ε)
+pairOpIsMonoid record { isSemigroup = isSemigroup ; identity = identity } = record
+  { isSemigroup = record
+    { isMagma = record
+      { isEquivalence = ×-isEquivalence
+          (IsMagma.isEquivalence (IsSemigroup.isMagma isSemigroup))
+          (IsMagma.isEquivalence (IsSemigroup.isMagma isSemigroup))
+      ; ∙-cong = λ (p , q) (p′ , q′)
+          → IsMagma.∙-cong (IsSemigroup.isMagma isSemigroup) p p′
+          , IsMagma.∙-cong (IsSemigroup.isMagma isSemigroup) q q′
+      }
+    ; assoc = pairOpAssoc (IsSemigroup.assoc isSemigroup)
+    }
+  ; identity = pairOpIdentity identity
+  }
+
+pairOpComm : Algebra.Commutative _≈_ _∙_ → Algebra.Commutative _≈ᵖ_ _∙ᵖ_
+pairOpComm comm (a , b) (c , d) =
+  ×-refl (comm a c) (comm b d) {ε , ε}
+
+pairOpRespectsComm :
+  IsCommutativeMonoid _≈_ _∙_ ε → IsCommutativeMonoid _≈ᵖ_ _∙ᵖ_ (ε , ε)
+pairOpRespectsComm record { isMonoid = isMonoid ; comm = comm } = record
+  { isMonoid = pairOpIsMonoid isMonoid ; comm = pairOpComm comm }