proposition: Lemma um_unitbPtUn k v f : unitb (pts k v \+ f) = false.
proof: Proof. by rewrite um_unitbUn um_unitbPt. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)