{A B : Type} {f g : A -> B} (p : forall x, f x = g x) {x y : A} (q : x = y) {z : B} (s : g y = z) : (ap f q) @ (p y @ s) = (p x) @ (ap g q @ s). Proof. destruct q, s; cbn. apply concat_1p. Defined.
Require Import Basics.Overture Basics.Tactics.