Consider the following premises. U(d) -> q_2. forall z: U(z) or T_4(z). T_4(d) -> q_2. q_2 -> T_4(d). Can we infer q_2 from them? If possible, name the inference rules being used at each step.
 From forall z: U(z) or T_4(z) we can infer U(d) or T_4(d) via universal instantiation. From q_2 -> T_4(d), T_4(d) -> q_2 we can infer q_2 <-> T_4(d) via biconditional introduction. From q_2 <-> T_4(d) we can infer T_4(d) -> q_2 via biconditional elimination. Finally, from U(d) -> q_2, T_4(d) -> q_2, U(d) or T_4(d) we can infer q_2 via disjunction elimination. Therefore, the answer is yes.