{A} {P : A -> Type} {a0 a1 a2} {p : a0 = a1} {q : a1 = a2} {b0 : P a0} {b1 : P a1} {b2 : P a2} : DPath P p b0 b1 -> DPath P q b1 b2 -> DPath P (p @ q) b0 b2. Proof. destruct p, q. exact concat. Defined.
Require Import Basics. Require Import Types.Paths Types.Sigma Types.Forall.