Consider the following premises. S_12(a_12) -> s_1. forall x_12: S_2(x_12) -> S_12(x_12). s_1 -> S_2(a_12). Can we infer s_1 -> S_2(a_12) from them? If possible, name the inference rules being used at each step.
That is one of the premises. Therefore, the answer is yes.