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_12: W_2(x_12) <-> Q_3(x_12). exists x_12: Q_3(x_12) -> ~Q_4(x_12). forall x_12: Q_4(x_12). forall x_12: Q_3(x_12) -> W_2(x_12).
exists x_12: ~Q_3(x_12) can be inferred via the existential modus tollens rule. forall x_12: W_2(x_12) -> Q_3(x_12) can be inferred via the universal biconditional elimination rule. forall x_12: Q_3(x_12) -> W_2(x_12) can be inferred via the universal biconditional elimination rule.