proposition: Lemma umfilt_predT f : um_filter predT f = f.
proof: Proof. by apply: omap_some. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)