Vague XML querying in peer-to-peer networks

We study the problem of querying XML data in peer-topeer networks without resorting to the use of a global schema or semantic mappings between local schemas. We first propose a query language aimed at ensuring autonomy to the participating peers. The language enables "vague" query evaluation, i.e., computation of answers that satisfy new queries obtained from the original ones through proper transformations. In addition, we analyze the issues related to the problem of combining partial answers coming from different peers using knowledge about limited portions of the local schemas, and discuss a preliminary proposal for a suitable semantics. Finally, we propose an architecture for the support of the language.