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) -> S(x_13). u or ~Q_13(a_12). forall x_13: S(x_13) -> Q_13(x_13).
Q_13(a_12) -> u. forall x_13: Q_13(x_13) <-> S(x_13). forall x_13: S(x_13) <-> Q_13(x_13).