proposition: Lemma msetICA A B C : A `&` (B `&` C) = B `&` (A `&` C).
proof: Proof. by rewrite !msetIA (msetIC A). Qed.
imports: mathcomp(ssreflect ssrbool ssrnat eqtype ssrfun seq) mathcomp(choice path finset finfun fintype bigop tuple) finmap