Consider the following premises. S(a_11) -> u_4. forall x_11: S(x_11) and S_11(x_11). Can we infer u_4 from them? If possible, name the inference rules being used at each step.
 From forall x_11: S(x_11) and S_11(x_11) we can infer S(a_11) and S_11(a_11) via universal instantiation. From S(a_11) and S_11(a_11) we can infer S(a_11) via simplification. Finally, from S(a_11) -> u_4, S(a_11) we can infer u_4 via modus ponens. Therefore, the answer is yes.