What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Susan is taking a plane if and only if Thomas is sleeping. Susan is not playing tennis. For all z, z will take a plane if and only if z will play tennis.
If Susan takes a plane, then Thomas is sleeping. If Thomas sleeps, then Susan is taking a plane. For all z, if z takes a plane, then z is playing tennis. For all z, if z plays tennis, then z is taking a plane.