What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all z, if z were a bartender, then z is happy. For all z, if z were happy, then z is a bartender. For all z, z is happy if and only if z is poor. For all z, z is not poor.
For all z, z is a bartender if and only if z is happy. For all z, z is happy if and only if z is a bartender. For all z, if z were happy, then z is poor. For all z, if z were poor, then z is happy. For all z, z is not happy.