proposition: Lemma eqEmproper A B : (A == B) = (A `<=` B) && ~~ (A `<` B).
proof: Proof. by rewrite negb_and negbK andb_orr andbN eqEmsubset. Qed.
imports: mathcomp(ssreflect ssrbool ssrnat eqtype ssrfun seq) mathcomp(choice path finset finfun fintype bigop tuple) finmap