What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall y_4: U_3(y_4) -> T_4(y_4). T_4(a_17) -> s. s -> U_3(a_17). U_3(a_17).
T_4(a_17) -> U_3(a_17). exists x: U_3(x).