proposition: Lemma ltRS x : x < x + 1.
proof: Proof. by rewrite -subR_le0 (addRC x) addRK. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div order) mathcomp(ssralg ssrnum ssrint rat intdiv) Coq(Morphisms Setoid) fourcolor(real realsyntax)