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_1: W_2(y_1) -> U(y_1). forall y_1: U(y_1) <-> W_2(y_1).
forall y_1: U(y_1) -> W_2(y_1) can be inferred via the universal biconditional elimination rule. forall y_1: W_2(y_1) -> U(y_1) can be inferred via the universal biconditional elimination rule.