proposition: Lemma dom_lastkey0PN A (h : natmap A) : last_key h != 0 <-> dom h != [::].
proof: Proof. by split; move/eqP=>H; apply/eqP=>X; elim: H; apply/dom_lastkey0P. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path interval) pcm(options prelude pred finmap rtc seqext useqord uslice uconsec)