Global Instance eqk_equiv : Equivalence eqk.Global Instance eqke_equiv : Equivalence eqke.

(* Specifications: *)
Lemma InA_eqke_eqk : forall x m, InA eqke x m -> InA eqk x m.
Lemma InA_eqk : forall p q m, eqk p q -> InA eqk p m -> InA eqk q m.