proposition: Lemma validPt k v : valid (pts k v : U) = C k.
proof: Proof. by rewrite ptsU validU valid_unit andbT. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)