Consider the following premises. forall x_3: U(x_3) -> S(x_3). forall x_3: S(x_3) -> U(x_3). exists x_3: S(x_3) -> U(x_3). Can we infer exists x_3: S(x_3) -> U(x_3) from them? If possible, name the inference rules being used at each step.
That is one of the premises. Therefore, the answer is yes.