Consider the following premises. r_2 <-> U(d). forall y_1: U(y_1). Can we infer r_2 from them?
 From forall y_1: U(y_1) we can infer U(d). From r_2 <-> U(d) we can infer U(d) -> r_2. Finally, from U(d) -> r_2, U(d) we can infer r_2. Therefore, the answer is yes.