Concurrent Markup for XML Documents

Abstract The implementation,of concurrent markup,by Durusau and O'Donnell (Extreme Markup 2001) relies upon related but separate principles. First, markup, commonly described in tree notation, is actually metadata about PCDATA. Second, the membership of any "atom of PCDATA" ,in a given hierarchy can be recorded as metadata for that PCDATA. These two principles have allowed the authoring and querying of overlapping hierarchies using standard XML software. This presentation moves beyond the use of text snippets to illustrate overlapping hierarchies and