What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? Name the inference rule being used: John is sleeping. If it is cold, then Barbara is a nurse. If Barbara were a nurse, then John is not sleeping.
Barbara is not a nurse can be inferred via the modus tollens rule. If it is cold, then John is not sleeping can be inferred via the transitivity rule.