Consider the following premises. forall y_1: Q(y_1) <-> T(y_1). forall y_1: Q(y_1) <-> P(y_1). Can we infer forall y_1: P(y_1) -> T(y_1) from them? If possible, name the inference rules being used at each step.
 From forall y_1: Q(y_1) <-> T(y_1) we can infer forall y_1: Q(y_1) -> T(y_1) via universal biconditional elimination. From forall y_1: Q(y_1) <-> P(y_1) we can infer forall y_1: P(y_1) -> Q(y_1) via universal biconditional elimination. Finally, from forall y_1: P(y_1) -> Q(y_1), forall y_1: Q(y_1) -> T(y_1) we can infer forall y_1: P(y_1) -> T(y_1) via universal transitivity. Therefore, the answer is yes.