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: exists x_15: Q_15(x_15) <-> P(x_15). forall x_15: P_15(x_15). forall x_15: P_15(x_15) -> Q_15(x_15).
forall x_15: Q_15(x_15) can be inferred via the universal modus ponens rule. exists x_15: Q_15(x_15) -> P(x_15) can be inferred via the existential biconditional elimination rule. exists x_15: P(x_15) -> Q_15(x_15) can be inferred via the existential biconditional elimination rule.