proposition: Lemma findPt k v : find k (pts k v : U) = if C k then Some v else None.
proof: Proof. by rewrite ptsU findU eq_refl /= 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)