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 y_3: U(y_3) <-> S(y_3). forall y_3: ~S(y_3). forall y_3: T_4(y_3) -> U(y_3).
exists y_3: U(y_3) -> S(y_3) can be inferred via the existential biconditional elimination rule. exists y_3: S(y_3) -> U(y_3) can be inferred via the existential biconditional elimination rule. exists y_3: ~U(y_3) can be inferred via the existential biconditional elimination rule.