proposition: Lemma Rlt_pos_pos_Rmult: forall r1 r2 : R, 0 < r1 -> 0 < r2 * r1 -> 0< r2.
proof: Proof. intros r1 r2 Hr2 Hr12; stepr ((r2*r1)*/r1); try field; auto; apply (Rle_mult_inv_pos _ _ Hr12 Hr2). Qed.
imports: Coq(Reals) Coq(Lra) Coq(Fourier) Coq(Euclid) Coq(Lia)