proposition: Lemma le_ceil x : x \is Rreal -> x <= (ceil x)%:~R.
proof: Proof. by move=> /ceil_itv /andP[]. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(fintype bigop order ssralg poly ssrnum ssrint)