proposition: Lemma Rdiv_lt_1 : forall r1 r2, 0 < r2 -> (r1 < r2 <-> r1 / r2 < 1).
proof: Proof. intros. pattern r2 at 1. rewrite <- (Rmult_1_l r2). split ; apply Rlt_div_l ; apply H. Qed.
imports: Coq(Reals Psatz ssreflect) Coq(ssrbool) mathcomp(seq)