proposition: Lemma InPtUnL k v f : valid (pts k v \+ f) -> (k, v) \In pts k v \+ f.
proof: Proof. by move/InPtUnE=>->; left. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)