What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall y_1: P(y_1) -> R(y_1). forall y_1: ~S(y_1). exists y_1: S(y_1) <-> R(y_1). forall y_1: R(y_1) -> P(y_1).
forall y_1: P(y_1) <-> R(y_1). forall y_1: R(y_1) <-> P(y_1). exists y_1: S(y_1) -> R(y_1). exists y_1: R(y_1) -> S(y_1). exists y_1: ~R(y_1).