proposition: Lemma bin_gt0 n m : (0 < 'C(n, m)) = (m <= n).
proof: Proof. by elim: n m => [|n IHn] [|m] //; rewrite addn_gt0 !IHn orbC ltn_neqAle andKb. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq path) mathcomp(div fintype tuple finfun bigop prime finset)