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: U(y) <-> W(y). forall y: P_1(y) -> U(y). exists y: W(y) -> P_1(y).
exists y: W(y) -> U(y) can be inferred via the existential 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.