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