proposition: Lemma complI x y : ~` (x `&` y) = ~` x `|` ~` y.
proof: Proof. by rewrite !complE diffxI. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)