From Boolean to fuzzy algebraic queries in a possibilistic database framework

This paper is situated in the area of databases containing ill-known values represented by possibility distributions. Some previous works have shown that it was possible to define a possibilistic database mode! that is a strong representation system for a query language including four algebraic operators (selection, projection, fk-join and union). The strong representation system property guarantees that the query evaluation process does not have to make the interpretations of the database explicit. In this paper we study the extension of this query language to the case where queries may involve fuzzy terms and we investigate the impact of such an extension on the model.