fact: Definition tE {A n} (v : t A (S n)) : v = cons (hd v) (tail v) := (match v in t _ m return (match m return t A m -> Type with O => fun _ => Unit | S k => fun v => v = (cons (hd v) (tail v)) end) v with nil => tt | cons _ a w => 1%path end).
imports: Coq(ssreflect) HoTT(HoTT) HoTT_additions Hierarchy Param_nat