proposition: Lemma ltR0Sn n : 0 < n.+1.
proof: Proof. by elim: n => // n IHn; apply: ltR_trans IHn _; apply: ltRS. Qed.
imports: mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat div order) mathcomp(ssralg ssrnum ssrint rat intdiv) Coq(Morphisms Setoid) fourcolor(real realsyntax)