proposition: Lemma intrKceil : cancel intr ceil.
proof: Proof. by move=> m; apply/eqP; rewrite eqr_oppLR -mulrNz intrKfloor. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg poly ssrnum ssrint)