proposition: Lemma eval_undef a p z0 : eval a p undef z0 = z0.
proof: Proof. by rewrite /eval oev_undef. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)