Consider the following premises. t_1 -> U(a_17). forall x_17: U(x_17) -> S_17(x_17). S_17(a_17) -> t_1. S_17(a_17). Can we infer t_1 from them? If possible, name the inference rules being used at each step.
 From forall x_17: U(x_17) -> S_17(x_17) we can infer U(a_17) -> S_17(a_17) via universal instantiation. From t_1 -> U(a_17), U(a_17) -> S_17(a_17) we can infer t_1 -> S_17(a_17) via transitivity. From S_17(a_17) -> t_1, t_1 -> S_17(a_17) we can infer S_17(a_17) <-> t_1 via biconditional introduction. From S_17(a_17) <-> t_1 we can infer S_17(a_17) -> t_1 via biconditional elimination. Finally, from S_17(a_17) -> t_1, S_17(a_17) we can infer t_1 via modus ponens. Therefore, the answer is yes.