Consider the following premises. forall x_12: U(x_12) or S_12(x_12). p -> ~S_12(f_2). ~U(f_2). Can we infer ~p from them?
 From forall x_12: U(x_12) or S_12(x_12) we can infer U(f_2) or S_12(f_2). From U(f_2) or S_12(f_2), ~U(f_2) we can infer S_12(f_2). Finally, from p -> ~S_12(f_2), S_12(f_2) we can infer ~p. Therefore, the answer is yes.