It is also common to consider the always true formula and the always false formula to be connective (in which case they are nullary). True formula: , , (prefix), or ; False formula: , , (prefix), or .
It is also common to consider the always true formula and the always false formula to be connective (in which case they are nullary). True formula: , , (prefix), or ; False f,ormula:  , (prefix), or .