proposition: Lemma lt_pair (x1 y1 : T) (x2 y2 : T') : (x1, x2) < (y1, y2) :> T * T' = [&& (x1 != y1) || (x2 != y2), x1 <= y1 & x2 <= y2].
proof: Proof. by rewrite ltEprod negb_and. Qed.
imports: HB(structures) mathcomp(ssreflect ssrfun ssrbool eqtype ssrnat choice seq) mathcomp(path fintype tuple bigop finset div prime finfun) mathcomp(finset)