Consider the following premises. forall x: ~R_3(x). forall x: R_3(x) <-> T(x). forall x: T(x) <-> R_3(x). Can we infer forall x: ~T(x) from them?
 From forall x: T(x) <-> R_3(x) we can infer forall x: R_3(x) -> T(x). From forall x: R_3(x) <-> T(x) we can infer forall x: T(x) -> R_3(x). From forall x: T(x) -> R_3(x), forall x: R_3(x) -> T(x) we can infer forall x: T(x) <-> R_3(x). Finally, from forall x: T(x) <-> R_3(x), forall x: ~R_3(x) we can infer forall x: ~T(x). Therefore, the answer is yes.