Date Added: Oct 2011
This paper provides a formal specification in Z of a conceptual model for an XML document called Graph-Document Type Definition (G-DTD). This model has been used for describing XML documents at the schema level and also assists the user to arrange the content of XML documents. More importantly G-DTD can be used as a tool to simplify the XML document design in a simple and precise way. The specification presented here provides a formal account of the state and operation of this model and a sound basis for instantiations of the model to be built.