What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? There is at least one z for which z is a taxi driver if and only if z is rich. For all z, z is a taxi driver. For all z, if z were rich, then z is taking a plane.
There is at least one z for which if z were a taxi driver, then z is rich. There is at least one z for which if z were rich, then z is a taxi driver.