What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? forall x_13: Q_13(x_13) -> R_13(x_13). R_13(a_12) -> P_13(a_12). ~r_2. forall x_13: P_13(x_13) -> Q_13(x_13). r_2 <-> P_13(a_12).
r_2 -> P_13(a_12). P_13(a_12) -> r_2. ~P_13(a_12). forall x_13: P_13(x_13) -> R_13(x_13).