proposition: Lemma OT_order_le_reflexive x: order_type x -> x <=t x.
proof: Proof. move=> ox; split => //; exists (identity (substrate x)); exists (substrate x). split; first by fprops. move: (OT_prop2 ox) => orx. rewrite (iorder_substrate orx); exact: (identity_is orx). Qed.
imports: mathcomp(ssreflect ssrbool ssrfun eqtype)