Consider the following premises. forall y_2: U(y_2) or ~P_5(y_2). P_5(a_5). Can we infer forall y_2: ~U(y_2) from them?
 From P_5(a_5) we can infer exists y_2: P_5(y_2). From forall y_2: U(y_2) or ~P_5(y_2) we can infer forall y_2: P_5(y_2) -> U(y_2). Finally, from forall y_2: P_5(y_2) -> U(y_2), exists y_2: P_5(y_2) we can infer exists y_2: U(y_2), which contradicts forall y_2: ~U(y_2). Therefore, the answer is no.