A first approach to possibilistic queries addressed to possibilistic databases

It is now recognized that querying databases containing imprecise information raises several problems, including that of complexity. The authors consider a new kind of query, called possibilistic queries, of the form "to what extent is it possible that a given tuple t belongs to the answer of Q (a regular relational query)". The paper is a first attempt to show that a reasonable complexity can be expected for a specified subset of possibilistic queries.