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_4: W(x_4) -> T_3(x_4). forall x_4: ~T_3(x_4). forall x_4: T_3(x_4) -> W(x_4).
exists x_4: ~W(x_4) can be inferred via the existential modus tollens rule. exists x_4: W(x_4) <-> T_3(x_4) can be inferred via the existential biconditional introduction rule. exists x_4: T_3(x_4) <-> W(x_4) can be inferred via the existential biconditional introduction rule.