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_3: T_2(y_3) -> R(y_3). exists y_3: R(y_3) -> T_2(y_3). forall y_3: ~U(y_3). forall y_3: T_2(y_3) <-> U(y_3).
exists y_3: R(y_3) <-> T_2(y_3) can be inferred via the existential biconditional introduction rule. exists y_3: T_2(y_3) <-> R(y_3) can be inferred via the existential biconditional introduction rule. forall y_3: T_2(y_3) -> U(y_3) can be inferred via the universal biconditional elimination rule. forall y_3: U(y_3) -> T_2(y_3) can be inferred via the universal biconditional elimination rule. forall y_3: ~T_2(y_3) can be inferred via the universal biconditional elimination rule.