Truth-Functionality, Rough Sets and Three-Valued Logics

This paper investigates the significance of truth-functional three valued logics of ill-known sets described by pairs of disjoint (or pairs of nested) subsets. In particular the case of three-valued logics of rough sets is studied in more details, showing that, while the mathematical underpinnings are sound, the relevance of these logics for reasoning about data-tables containing incomplete descriptions of objects is questionable.