proposition: Lemma le_introl : forall i j :nat, (i<= j)%nat -> inl i o<= inl j.
proof: Proof. intros i j H; destruct (Compat815.le_lt_or_eq _ _ H); auto . - left; now constructor. - subst; now right. Qed.
imports: Coq(Arith Compare_dec Lia) hydras(Comparable Simple_LexProd ON_Generic ON_plus ON_Omega Compat815)