(** ** Intersection of relations *)

Definition rel_inter {A B} (R1 R2: rel A B): rel A B :=
  fun x y => R1 x y /\ R2 x y.Infix "/\" := rel_inter : rel_scope.Global Instance rel_inter_params:
  Params (@rel_inter) 4.

Lemma rel_inter_rexists {A B} (R1 R2: rel A B) x y: RExists (R1 x y /\ R2 x y) (R1 /\ R2) x y.