What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Linda is not listening to a song. If William were a nurse, then Linda is listening to a song. If Linda listens to a song, then William is a nurse.
William is not a nurse. William is a nurse if and only if Linda is listening to a song. Linda is listening to a song if and only if William is a nurse.