fact: Definition path_sig_hprop {A} {P : A -> Prop} (P_hprop : forall (x : A) (p q : P x), p = q) (u v : @sig A P) (p : proj1_sig u = proj1_sig v) : u = v := path_sig u v p (P_hprop _ _ _).
imports: Fiat.Common.Equality