proposition: Lemma eval_umfilt p z0 f a : eval a p f z0 = eval a xpredT (um_filter p f) z0.
proof: Proof. by rewrite eval_predI; apply: eq_filt_eval; apply/eq_in_umfilt. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)