Consider the following premises. forall x_13: P_3(x_13) -> T_4(x_13). forall x_13: T_4(x_13) -> U_4(x_13). forall x_13: P_13(x_13) <-> U_4(x_13). forall x_13: T(x_13) -> P_13(x_13). forall x_13: P_3(x_13). Can we infer forall x_13: U_4(x_13) from them?
 From forall x_13: P_13(x_13) <-> U_4(x_13) we can infer forall x_13: P_13(x_13) -> U_4(x_13). From forall x_13: T(x_13) -> P_13(x_13), forall x_13: P_13(x_13) -> U_4(x_13) we can infer forall x_13: T(x_13) -> U_4(x_13). From forall x_13: P_3(x_13) -> T_4(x_13), forall x_13: P_3(x_13) we can infer forall x_13: T_4(x_13). From forall x_13: T_4(x_13) we can infer forall x_13: T_4(x_13) or T(x_13). Finally, from forall x_13: T_4(x_13) -> U_4(x_13), forall x_13: T(x_13) -> U_4(x_13), forall x_13: T_4(x_13) or T(x_13) we can infer forall x_13: U_4(x_13). Therefore, the answer is yes.