Consider the following premises. t and q_14. t_3 -> ~q_1. t -> q_1. Can we infer t_3 from them? If possible, name the inference rules being used at each step.
 From t and q_14 we can infer t via simplification. From t -> q_1, t we can infer q_1 via modus ponens. Finally, from t_3 -> ~q_1, q_1 we can infer ~t_3 via modus tollens, which contradicts t_3. Therefore, the answer is no.