Management of multihierarchical XML encodings has attracted attention of a number of researchers both in databases [8] and in humanities[10]. Encoding documents using multiple hierarchies can yield overlapping markup. Previously proposed solutions to management of document-centric XML with overlapping markup rely on the XML expertise of humans and their ability to maintain correct schemas for complex markup languages.We demonstrate a unified solution for management of complex, multihierarchical document-centric XML. Our framework includes software for storing, parsing, in-memory access, editing and querying, multihierarchical XML documents with conflicting structures.

The process of creation of document-centric XML documents often starts with a prepared textual content, into which the editor introduces markup. In such situations, intermediate XML is almost never valid with respect to the DTD/Schema used for the encoding. At the same time, it is important to ensure that at each moment of time, the editor is working with an XML document that can enriched with further markup to become valid. In this paper we introduce the notion of potential validity of XML documents, which allows us to distinguish between XML documents that are invalid because the encoding is simply incomplete and XML documents that are invalid because some of the DTD rules guiding the structure of the encoding were violated during the markup process. We give a linear-time algorithm for checking potential validity for documents.