joint work with Shunichi Amano and Leonid Libkin

Relational schema mappings have been extensively studied in connection with data integration and exchange problems, but mappings between XML schemas have not received the same amount of attention. I will present an attempt to develop a theory of expressive XML schema mappings. Such mappings should be able to use various forms of navigation in a document, and specify conditions on data values. I will introduce a language for XML schema mappings, and concentrate on two decision problems: - consistency: is it possible to map some document of a source schema into a document of the target schema? - absolute consistency: can all documents of a source schema be mapped?