What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? It is cold if and only if David is an astronaut. Richard is driving a car. James is not a nurse. James is a nurse if and only if it is cold.
Richard is driving a car and James is not a nurse. James is not a nurse and Richard is driving a car. If it is cold, then David is an astronaut. If James were a nurse, then it is cold. If David were an astronaut, then it is cold. If it is cold, then James is a nurse. It is not cold.