proposition: Lemma mem_remf1 f (k' k : K) : k \in f.[~ k'] = (k != k') && (k \in f) :> bool.
proof: Proof. by rewrite mem_remf inE. Qed.
imports: HB(structures) mathcomp(ssreflect ssrbool ssrnat eqtype ssrfun seq) mathcomp(choice path finset finfun fintype bigop)