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_1: R(x_1) -> T_3(x_1). forall x_1: R(x_1) <-> S(x_1). exists x_1: T_3(x_1) -> S_4(x_1).
exists x_1: R(x_1) -> S_4(x_1) can be inferred via the existential transitivity rule. forall x_1: R(x_1) -> S(x_1) can be inferred via the universal biconditional elimination rule. forall x_1: S(x_1) -> R(x_1) can be inferred via the universal biconditional elimination rule.