Consider the following premises. forall x_20: P_20(x_20) or Q_20(x_20). forall x_20: P_16(x_20) -> ~Q_20(x_20). t_1 -> P_16(i). forall x_20: ~P_20(x_20). Can we infer ~t_1 or t from them? If possible, name the inference rules being used at each step.
 From forall x_20: P_20(x_20) or Q_20(x_20), forall x_20: ~P_20(x_20) we can infer forall x_20: Q_20(x_20) via universal disjunctive syllogism. From forall x_20: P_16(x_20) -> ~Q_20(x_20), forall x_20: Q_20(x_20) we can infer forall x_20: ~P_16(x_20) via universal modus tollens. From forall x_20: ~P_16(x_20) we can infer ~P_16(i) via universal instantiation. From t_1 -> P_16(i), ~P_16(i) we can infer ~t_1 via modus tollens. Finally, from ~t_1 we can infer ~t_1 or t via addition. Therefore, the answer is yes.