Vaguely Defined Objects : Representations, Fuzzy Sets and Nonclassical Cardinality Theory (Theory and Decision Library B) (Reprint)

Classical two-valued logic and the related notion of a set, together with its mathematical consequences, are then often inadequate or insufficient formal tools, and can even become useless for applications because of their (too) categorical character: 'true - false', 'belongs - does not belong', 'is - is not', 'black - white', '0 - 1', etc.