proposition: Lemma msubsetIr A B : A `&` B `<=` B.
proof: Proof. by apply/msubsetP=> x; rewrite msetE geq_minr. Qed.
imports: mathcomp(ssreflect ssrbool ssrnat eqtype ssrfun seq) mathcomp(choice path finset finfun fintype bigop tuple) finmap