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: T(x) -> T_1(x). exists x: T_1(x) -> R_4(x). forall x: R_4(x) <-> T(x).
exists x: T(x) -> R_4(x) can be inferred via the existential transitivity rule. forall x: R_4(x) -> T(x) can be inferred via the universal biconditional elimination rule. forall x: T(x) -> R_4(x) can be inferred via the universal biconditional elimination rule.