proposition: Lemma ltrDr x y : (x < y + x) = (0 < y).
proof: Proof. by rewrite -{1}[x]add0r lterD2. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat seq choice) mathcomp(ssrAC div fintype path bigop order finset fingroup) mathcomp(ssralg poly)