fact: Definition echelon_recdef_prop c (p: Set -> Set -> Set -> Set):= forall g1 g2 i, i <c slength c -> (forall j, j <c i -> Vg g1 j = Vg g2 j) -> p g1 (P (Vg c i)) (Q (Vg c i)) = p g2 (P (Vg c i)) (Q (Vg c i)).
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq)