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: W_4(x) -> U(x). forall x: T_4(x) or ~R(x). exists x: U(x) <-> R(x). forall x: T_4(x) -> W_4(x).
forall x: T_4(x) -> U(x) can be inferred via the universal transitivity rule. forall x: R(x) -> T_4(x) can be inferred via the universal rewriting rule. exists x: U(x) -> R(x) can be inferred via the existential biconditional elimination rule. exists x: R(x) -> U(x) can be inferred via the existential biconditional elimination rule.