What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If Richard sleeps, then Elisabeth is working. Elisabeth is working if and only if it is cold. If Elisabeth works, then Richard is sleeping.
Richard is sleeping if and only if Elisabeth is working. Elisabeth is working if and only if Richard is sleeping. If Elisabeth works, then it is cold. If it is cold, then Elisabeth is working.