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 y: Q_3(y) -> U(y). exists y: Q_3(y) <-> P(y). forall y: U(y) -> Q(y).
forall y: Q_3(y) -> Q(y) can be inferred via the universal transitivity rule. exists y: Q_3(y) -> P(y) can be inferred via the existential biconditional elimination rule. exists y: P(y) -> Q_3(y) can be inferred via the existential biconditional elimination rule.