What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Thomas is not a scientist. David is not a police officer. Richard is happy if and only if David is a police officer. If David were a server, then Charles is a bartender. Charles is a bartender if and only if Thomas is a scientist.
Thomas is not a scientist and David is not a police officer. David is not a police officer and Thomas is not a scientist. If Richard were happy, then David is a police officer. If Charles were a bartender, then Thomas is a scientist. If David were a police officer, then Richard is happy. If Thomas were a scientist, then Charles is a bartender. Richard is not happy. Charles is not a bartender.