What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: forall x_7: T_1(x_7) <-> S_7(x_7). u -> T_1(d). S_7(d) or u.
forall x_7: T_1(x_7) -> S_7(x_7) can be inferred via the universal biconditional elimination rule. forall x_7: S_7(x_7) -> T_1(x_7) can be inferred via the universal biconditional elimination rule.