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 z: Q_3(z) <-> U_3(z). forall z: Q_3(z) <-> U_3(z).
forall z: Q_3(z) -> U_3(z) can be inferred via the universal biconditional elimination rule. exists z: Q_3(z) -> U_3(z) can be inferred via the existential biconditional elimination rule. forall z: U_3(z) -> Q_3(z) can be inferred via the universal biconditional elimination rule. exists z: U_3(z) -> Q_3(z) can be inferred via the existential biconditional elimination rule.