#[global]
Hint Resolve Rmult_le_compat_r: real.

(* Specifications: *)
Lemma Rmult_ge_compat_l :
forall r r1 r2, r >= 0 -> r1 >= r2 -> r * r1 >= r * r2.
Lemma Rmult_ge_compat_r :
forall r r1 r2, r >= 0 -> r1 >= r2 -> r1 * r >= r2 * r.
Lemma Rmult_le_compat :
forall r1 r2 r3 r4,
0 <= r1 -> 0 <= r3 -> r1 <= r2 -> r3 <= r4 -> r1 * r3 <= r2 * r4.