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 if z sleeps, then z is taking a plane. For all z, z will not take a plane. For all z, if z takes a plane, then z is sleeping. For all z, if z takes a plane, then z is sleeping.
There is at least one z for which z will not sleep. There is at least one z for which z will sleep if and only if z will take a plane. There is at least one z for which z will sleep if and only if z will take a plane. There is at least one z for which z will take a plane if and only if z will sleep. There is at least one z for which z will take a plane if and only if z will sleep.