{A : Sequence} (x : sig A) (k : nat) : (x^++)^++k = x^++(k.+1). Proof. induction k as [ | k q]. - reflexivity. - exact (ap seq_pair_shift q). Defined.
Require Import Basics. Require Import Types. Require Import Diagrams.Diagram. Require Import Diagrams.Sequence. Require Import Diagrams.Cocone. Require Import Colimits.Colimit. Require Import Spaces.Nat.Core. Require Import Homotopy.IdentitySystems.