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_17: Q_14(x_17) -> Q_12(x_17). forall x_17: P_17(x_17) <-> Q_12(x_17). P_17(a_17).
exists x: P_17(x) can be inferred via the existential generalization rule. forall x_17: P_17(x_17) -> Q_12(x_17) can be inferred via the universal biconditional elimination rule. forall x_17: Q_12(x_17) -> P_17(x_17) can be inferred via the universal biconditional elimination rule.