#[local]
Hint Resolve ltk_trans ltk_not_eqk ltk_not_eqke : ordered_type.
#[local]
Hint Immediate eqk_sym eqke_sym : ordered_type.
Global Instance eqk_equiv : Equivalence eqk.
Global Instance ltk_compat' : Proper (eqke==>eqke==>iff) ltk.
(* Additional facts *)

Lemma ltk_eqk : forall e e' e'', ltk e e' -> eqk e' e'' -> ltk e e''.
#[local]
Hint Resolve eqk_not_ltk : ordered_type.