proposition: Lemma In_umfiltv p x f : x \In f -> p x.2 -> x \In um_filterv p f.
proof: Proof. by apply: In_umfiltX. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)