proposition: Lemma snumden_pos x: 0 <=x -> snumden' x = (snumden x).+1.
proof: Proof. by move/snumden_pos'; rewrite /snumden; case: (snumden' x) => // [][]. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat) mathcomp(seq choice fintype order bigop ssralg) mathcomp(div ssrnum ssrint rat prime path binomial) mathcomp(tuple finset) gaia(fibm)