proposition: Lemma lezD1 x y : (x + 1 <= y) = (x < y).
proof: Proof. by rewrite addrC lez1D. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(fintype finfun bigop order ssralg countalg ssrnum) mathcomp(poly)