What can be inferred from the following premises in a single inference step (ignoring inferences that add new predicates or constants)? If Robert were a scientist, then it is cloudy. It is snowing if and only if Robert is a scientist. If it is cloudy, then Robert is a scientist. It is not snowing.
Robert is a scientist if and only if it is cloudy. It is cloudy if and only if Robert is a scientist. If it snows, then Robert is a scientist. If Robert were a scientist, then it is snowing. Robert is not a scientist.