Consider the following premises. forall x: U_4(x) -> P(x). forall x: P(x) -> R(x). forall x: R(x) -> W(x). exists x: U_4(x) <-> W(x). Can we infer exists x: U_4(x) <-> W(x) from them? If possible, name the inference rules being used at each step.
That is one of the premises. Therefore, the answer is yes.