proposition: Lemma setIDAC A B C : (A :\: B) :&: C = (A :&: C) :\: B.
proof: Proof. by rewrite !setDE setIAC. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrfun eqtype ssrnat div seq) mathcomp(choice fintype finfun bigop)