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: exists z_4: T(z_4) or ~U_1(z_4). forall z_4: U_1(z_4) <-> T(z_4).
exists z_4: U_1(z_4) -> T(z_4) can be inferred via the existential rewriting rule. forall z_4: U_1(z_4) -> T(z_4) can be inferred via the universal biconditional elimination rule. forall z_4: T(z_4) -> U_1(z_4) can be inferred via the universal biconditional elimination rule.