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