proposition: Lemma slt_sorted_lt ltT ks x y : transitive ltT -> sorted ltT ks -> y \in ks -> x <[ks] y -> ltT x y.
proof: Proof. by apply: sorted_index_ord. Qed.
imports: Coq(ssreflect ssrbool ssrfun) mathcomp(ssrnat eqtype seq path interval order) pcm(options prelude ordtype seqext)