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