Library Coq.Program.Combinators

Proofs about standard combinators, exports functional extensionality.

Author: Matthieu Sozeau Institution: LRI, CNRS UMR 8623 - University Paris Sud

Require Import Coq.Program.Basics.
Require Export FunctionalExtensionality.

Open Scope program_scope.

Composition has id for neutral element and is associative.

Lemma compose_id_left : forall A B (f : A -> B), id ∘ f = f.

Lemma compose_id_right : forall A B (f : A -> B), f ∘ id = f.

Lemma compose_assoc : forall A B C D (f : A -> B) (g : B -> C) (h : C -> D),
  h ∘ g ∘ f = h ∘ (g ∘ f).

Hint Rewrite @compose_id_left @compose_id_right : core.
Hint Rewrite <- @compose_assoc : core.

flip is involutive.

Lemma flip_flip : forall A B C, @flip A B C ∘ flip = id.

prod_curry and prod_uncurry are each others inverses.

Lemma prod_uncurry_curry : forall A B C, @prod_uncurry A B C ∘ prod_curry = id.

Lemma prod_curry_uncurry : forall A B C, @prod_curry A B C ∘ prod_uncurry = id.