proposition: Lemma stir1_small1 n p: n < p -> 'So(n,p) = 0.
proof: Proof. by move /subnKC => <-; rewrite addSn stir1_small. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype) mathcomp(ssrnat seq path div) mathcomp(fintype tuple finfun bigop finset binomial)