proposition: Lemma Sn_small x: 0 <= x < 1 -> Sn x = (1-x) ^-1.
proof: Proof. by rewrite /Sn; move/floor_small => ->; rewrite mul0r addr0. 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)