What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: forall x_13: P_13(x_13) -> Q_13(x_13). forall x_10: ~R_10(x_10). forall x_13: Q_13(x_13) -> P_13(x_13). Q_13(d) -> R_10(a_10).
forall x_13: P_13(x_13) <-> Q_13(x_13) can be inferred via the universal biconditional introduction rule. forall x_13: Q_13(x_13) <-> P_13(x_13) can be inferred via the universal biconditional introduction rule.