Consider the following premises. forall x_6: R_6(x_6) or S_6(x_6). ~S_6(a_6). ~R_6(a_6) or t. Can we infer ~t from them? If possible, name the inference rules being used at each step.
 From forall x_6: R_6(x_6) or S_6(x_6) we can infer R_6(a_6) or S_6(a_6) via universal instantiation. From R_6(a_6) or S_6(a_6), ~R_6(a_6) or t we can infer S_6(a_6) or t via resolution. Finally, from S_6(a_6) or t, ~S_6(a_6) we can infer t via disjunctive syllogism, which contradicts ~t. Therefore, the answer is no.