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: U(a_12) or ~T(a_12). forall y_4: T(y_4) <-> U(y_4).
T(a_12) -> U(a_12) can be inferred via the rewriting rule. forall y_4: T(y_4) -> U(y_4) can be inferred via the universal biconditional elimination rule. forall y_4: U(y_4) -> T(y_4) can be inferred via the universal biconditional elimination rule.