+let eqPref = ref (fun _ -> assert false);;
+let set_eqP t = eqPref := fun _ -> t;;
+
+let default_eqP() =
+ let uri = NUri.uri_of_string "cic:/matita/ng/Plogic/equality/eq.ind" in
+ let ref = NReference.reference_of_spec uri (NReference.Ind(true,0,2)) in
+ NCic.Const ref
+;;
+
+let equivalence_relation =
+ let uri = NUri.uri_of_string "cic:/matita/ng/properties/relations/eq_rel.con"
+ in
+ let ref = NReference.reference_of_spec uri (NReference.Fix(0,1,2))
+ in NCic.Const ref
+
+let setoid_eq =
+ let uri = NUri.uri_of_string "cic:/matita/ng/sets/setoids/eq.con" in
+ let ref = NReference.reference_of_spec uri (NReference.Fix(0,0,2))
+ in NCic.Const ref
+
+let set_default_eqP() = eqPref := default_eqP
+
+let set_reference_of_oxuri f =
+ let eqnew = function
+ _ ->
+ let r = f(UriManager.uri_of_string
+ "cic:/matita/logic/equality/eq.ind#xpointer(1/1)")
+ in
+ NCic.Const r
+ in
+ eqPref := eqnew
+;;
+
+