Consider the following premises. forall x_6: P_3(x_6) -> Q_6(x_6). forall x_6: R_6(x_6) <-> U(x_6). forall x_6: U(x_6) or P_3(x_6). exists x_6: Q_6(x_6) -> R_6(x_6). Can we infer forall x_6: R_6(x_6) <-> U(x_6) from them? If possible, name the inference rules being used at each step.
That is one of the premises. Therefore, the answer is yes.