(* Ugly tacty to resolve sign condition for R *)
Require Export RGroundTac.
(* Theorems to simplify the goal 0 ? x * y and x * y ? 0 where ? is < > <= >= *)

Theorem Rle_sign_pos_pos: forall x y, (0 <= x -> 0 <= y  -> 0 <= x * y)%R.
intros x y H; apply Rmult_le_pos; auto with real.