What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? It is windy if and only if John is sleeping. If it is windy, then Charles is poor. John is sleeping if and only if Charles is poor.
If it is windy, then John is sleeping. If John sleeps, then Charles is poor. If John sleeps, then it is windy. If Charles were poor, then John is sleeping.