What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? For all y_3, y_3 will sleep if and only if y_3 will play squash. It is overcast if and only if Sarah is playing squash. If Sarah sleeps, then it is overcast.
If it is overcast, then Sarah is playing squash. If Sarah plays squash, then it is overcast. For all y_3, if y_3 sleeps, then y_3 is playing squash. For all y_3, if y_3 plays squash, then y_3 is sleeping.