proposition: Lemma freePtUn k v f : valid (pts k v \+ f) -> free (pts k v \+ f) k = f.
proof: Proof. by move=>V'; rewrite freePtUn2 // eq_refl. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)