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