proposition: Lemma diffKI x y : y `&` diff x y = \bot.
proof: Proof. by congr pair; rewrite diffKI. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)