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 y: P(y) -> Q(y). forall y: Q(y) -> U(y). forall y: U(y) <-> W(y). exists y: W(y) or P(y).
forall y: P(y) -> U(y) can be inferred via the universal transitivity rule. forall y: U(y) -> W(y) can be inferred via the universal biconditional elimination rule. forall y: W(y) -> U(y) can be inferred via the universal biconditional elimination rule.