proposition: Lemma sle_last x k ks : uniq ks -> x \in ks -> x <=[ks] (last k ks).
proof: Proof. by apply: index_last_mono. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path interval order) pcm(options prelude ordtype seqext)