proposition: Lemma pcmPV (x : prodPCM U V) : valid x = valid x.1 && valid x.2.
proof: Proof. by []. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq bigop fintype finset) pcm(options axioms prelude seqperm pred seqext)