Consider the following premises. forall y_3: S(y_3) or ~U(y_3). forall y_3: S(y_3) -> U(y_3). exists y_3: S(y_3) -> U(y_3). Can we infer forall y_3: ~(U(y_3) -> S(y_3)) from them? If possible, name the inference rules being used at each step.
That contradicts the premises. Therefore the answer is no.