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 z: R_4(z) <-> U(z). forall z: P(z) <-> R_4(z). forall z: S(z) <-> P(z). forall z: ~S(z).
forall z: R_4(z) -> U(z) can be inferred via the universal biconditional elimination rule. forall z: P(z) -> R_4(z) can be inferred via the universal biconditional elimination rule. forall z: S(z) -> P(z) can be inferred via the universal biconditional elimination rule. forall z: U(z) -> R_4(z) can be inferred via the universal biconditional elimination rule. forall z: R_4(z) -> P(z) can be inferred via the universal biconditional elimination rule. forall z: P(z) -> S(z) can be inferred via the universal biconditional elimination rule. forall z: ~P(z) can be inferred via the universal biconditional elimination rule.