Consider the following premises. exists x_9: U_2(x_9) <-> P(x_9). forall x_9: P_4(x_9) <-> U_2(x_9). Can we infer exists x_9: U_2(x_9) <-> P(x_9) from them? If possible, name the inference rules being used at each step.
That is one of the premises. Therefore, the answer is yes.