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) <-> R_4(x). forall x: T(x) or U_1(x). forall x: ~R_4(x). forall x: S(x) <-> T(x).
forall x: S(x) -> T(x) can be inferred via the universal biconditional elimination rule. exists x: S(x) -> R_4(x) can be inferred via the existential biconditional elimination rule. forall x: T(x) -> S(x) can be inferred via the universal biconditional elimination rule. exists x: R_4(x) -> S(x) can be inferred via the existential biconditional elimination rule. exists x: ~S(x) can be inferred via the existential biconditional elimination rule.