intros p q H' H'0; apply Rle_antisym.
apply isMax_inv1 with (1 := H'0); auto.
elim H'0; intros H'1 H'2; elim H'2; intros H'3 H'4; apply H'4; clear H'2;
auto with real.
Qed.
(* It is monotone *)

Theorem MonotoneMax : MonotoneP isMax.
red in |- *.