Rough sets and three valued connectives
Résumé
Rough sets were defined almost 30 years ago by Z. Pawlak as an instrument to deal with uncertainty due to incompleteness of the available information. Since the begging attempts to relate them to three valued logics and algebraic semantics have been carried out. After showing the relationship among three-valued sets and rough sets, we introduce a systematic study of truth-functional connectives which are definable on these two collections. We discuss tsignificance of truth-functionality on rough sets showing that, while the mathematical underpinnings are sound, the application of these logics for reasoning about data-tables containing incomplete descriptions is not straightforward. Finally, we give an overview of the rough-sets algebraic structures.