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: p_2 -> U_4(b_3). forall x: ~S(x). forall x: S(x) <-> U_4(x).
forall x: S(x) -> U_4(x) can be inferred via the universal biconditional elimination rule. forall x: U_4(x) -> S(x) can be inferred via the universal biconditional elimination rule. forall x: ~U_4(x) can be inferred via the universal biconditional elimination rule.