Multiple hierarchies: new aspects of an old solution

Overlap in markup occurs where some markup structures do not nest, such as where the structural division of the text into lists, sections, etc., differs from the syntactic division of the text into sentences and phrases. The Multiple Annotation solution to this problem (redundant encoding in multiple forms) has many advantages: it is based on XML, the modeling of alternative annotations is possible, each level can be viewed separately, and new levels can be added at any time. But it has the significant disadvantage of independence of the separate files. These multiply annotated files can be regarded as an interrelated unit, with the text serving as the implicit link. Two representations of the information contained in the multiple files (one in Prolog and one in XML) can be programmatically derived and used together for editing, for inference, or for unification of the multiply annotated documents. Multiple hierarchies: new aspects of an old solution Table of