Consider the following premises. forall x: S(x). forall x: R_2(x). forall x: S(x) <-> T_3(x). Can we infer forall x: T_3(x) from them? If possible, name the inference rules being used at each step.
 From forall x: S(x) <-> T_3(x) we can infer forall x: S(x) -> T_3(x) via universal biconditional elimination. From forall x: S(x), forall x: R_2(x) we can infer forall x: S(x) and R_2(x) via universal conjunction. From forall x: S(x) and R_2(x) we can infer forall x: S(x) via universal simplification. Finally, from forall x: S(x) -> T_3(x), forall x: S(x) we can infer forall x: T_3(x) via universal modus ponens. Therefore, the answer is yes.