proposition: Lemma Rdiv_lt_0_compat : forall r1 r2 : R, 0 < r1 -> 0 < r2 -> 0 < r1 / r2.
proof: Proof. intros r1 r2 H1 H2. apply Rlt_div_r. apply H2. rewrite Rmult_0_l. apply H1. Qed.
imports: Coq(Reals Psatz ssreflect) Coq(ssrbool) mathcomp(seq)