proposition: Lemma omap_funP : f =1 omap (map_fun f).
proof: Proof. by case: f=>sort []. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path bigop) pcm(options prelude finmap seqperm pred seqext) pcm(pcm morphism)