+ NCicEnvironment.add_constraint true (mk_cprop a) (mk_cprop b);
+ NCicEnvironment.add_constraint true (mk_cprop a) (mk_type b);
+ NCicEnvironment.add_constraint true (mk_type a) (mk_cprop b);
+ NCicEnvironment.add_constraint false (mk_cprop a) (mk_type a);
+ NCicEnvironment.add_constraint false (mk_type a) (mk_cprop a);