Consider the following premises. u -> U(f). u. forall x_1: U(x_1) <-> T(x_1). Can we infer T(f) from them? If possible, name the inference rules being used at each step.
 From forall x_1: U(x_1) <-> T(x_1) we can infer forall x_1: U(x_1) -> T(x_1) via universal biconditional elimination. From forall x_1: U(x_1) -> T(x_1) we can infer U(f) -> T(f) via universal instantiation. From u -> U(f), U(f) -> T(f) we can infer u -> T(f) via transitivity. Finally, from u -> T(f), u we can infer T(f) via modus ponens. Therefore, the answer is yes.