An information processing system comprising at least one information processing unit (A, B). The information processing unit has at least one information processing member which resolves allowed values. Allowed values include at least one data value and at least one non-data value. At least one non-data value is a null value. The system further comprises a plurality of information transmission elements (OA, NA) for transmitting values to and from the information processing unit (A) and the information processing member.