proposition: Theorem mul_assoc_iso : forall a b c, (a * b) * c ≅ a * (b * c).
proof: Proof. intros; exists (fun p => match p with ((a, b), c) => (a, (b, c)) end); exists (fun p => match p with (a, (b, c)) => ((a, b), c) end). extensionalize. Qed.
imports: Hask.Ltac Hask.Prelude Hask.Control.Applicative Hask.Control.Monad Hask.Control.Monad.Cont Hask.Control.Monad.State Hask.Data.Functor.Contravariant Hask.Data.Functor.Identity Hask.Data.Functor.Kan Hask.Data.Functor.Yoneda Hask.Control.Lens Coq.Classes.Morphisms Coq.Setoids.Setoid Coq.Init.Datatypes Coq.Relations.Relation_Definitions FunctionalExtensionality