{A : Type} (P : A -> Type) (u v : sig P) (p q : u = v) (rs : {r : p..1 = q..1 & transport (fun x => transport P x u.2 = v.2) r p..2 = q..2}) : p = q. Proof. destruct rs, p, u. etransitivity; [ | apply eta_path_sigma ]. path_induction. reflexivity. Defined.
Require Import HoTT.Basics. Require Import Types.Arrow Types.Paths.