What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x_4: P_17(x_4) <-> Q(x_4). P_17(a_5). forall x_4: Q(x_4) -> P_17(x_4).
exists x: P_17(x). forall x_4: P_17(x_4) -> Q(x_4). forall x_4: Q(x_4) -> P_17(x_4).