 These three parameters admit of a total of eighteen combinations of their settings and hence eighteen bridge principles. The symbols in parentheses associated with each parameter setting combine to determine a unique label for each of the principles: The first letter indicates the scope of the deontic operator (C, W or B), the second letter indicates the type of deontic operator (o[bligation], p[ermissions], r[easons]) and the “+” or “−” indicate positive and negative polarity  respectively.[19]  For example, the label “Co+” corresponds to our original principle  IMP: