Hint Extern 2 (RIntro _ subrel _ (_ /\ _)%rel) =>
eapply rel_inter_glb : typeclass_instances.

(* Specifications: *)
Lemma rel_inter_refl {A} (R1 R2: rel A A):
Reflexive R1 ->
Reflexive R2 ->
Reflexive (R1 /\ R2).