proposition: Lemma omorph1 : f \top = \top.
proof: Proof. by rewrite -[\top in LHS]set_meet0 omorphSM image_set0 set_meet0. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype choice order) mathcomp(ssrnat bigop classical_sets)