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 x: P(x) -> ~W_4(x). forall x: W_4(x). forall x: U_2(x) -> P(x). exists x: P(x) -> U_2(x).
forall x: ~P(x) can be inferred via the universal modus tollens rule. exists x: P(x) <-> U_2(x) can be inferred via the existential biconditional introduction rule. exists x: U_2(x) <-> P(x) can be inferred via the existential biconditional introduction rule.