What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all x_15, if x_15 sleeps, then x_15 is a writer. For all x_15, x_15 will sleep if and only if x_15 is a nurse. There is at least one x_15 for which x_15 is a nurse. For all x_15, x_15 is not a writer.
For all x_15, x_15 will not sleep. For all x_15, if x_15 sleeps, then x_15 is a nurse. For all x_15, if x_15 were a nurse, then x_15 is sleeping.