Fixing Collaborative Edition on Typed Documents

Collaborative edition is achieved by distinct sites that work independently on (a copy of) a shared document. In pure Peer to Peer collaborative editing, no centralization nor locks nor timestamps, therefore convergence, i.e. all sites have the same copy of the shared document, is the main issue. When the editing operations defined on the data structure enjoy a commutation property, efficient algorithms can be designed. The XML language provides a widely used format for documents and these documents are usually typed by DTD's or XML Schemas that are subclasses of regular tree languages. We extend a collaborative editing algorithm that relies on a notion of semantics dependence for operations and a tree data structure implementing XML documents to handle type information provided by DTD's or XML Schemas (and more generally regular tree languages). We show that the algorithm is convergent and that the final document has the required type.