What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If Thomas plays tennis, then David is a police officer. If Richard sleeps, then Barbara is a bartender. For all y, y is not a bartender. If David were a police officer, then Thomas is playing tennis. Richard is sleeping if and only if Thomas is playing tennis.
Thomas is playing tennis if and only if David is a police officer. David is a police officer if and only if Thomas is playing tennis. If Richard sleeps, then Thomas is playing tennis. If Thomas plays tennis, then Richard is sleeping.