Consider the following premises. p -> ~t. forall x_12: R_12(x_12) or S_12(x_12). S_12(a_12) -> t. R_12(a_12) -> t. Can we infer ~p from them? If possible, name the inference rules being used at each step.
 From forall x_12: R_12(x_12) or S_12(x_12) we can infer R_12(a_12) or S_12(a_12) via universal instantiation. From R_12(a_12) -> t, S_12(a_12) -> t, R_12(a_12) or S_12(a_12) we can infer t via disjunction elimination. Finally, from p -> ~t, t we can infer ~p via modus tollens. Therefore, the answer is yes.