Access control and verification in Petri-net-based hyperdocuments

The Petri-net-based trellis model of hypertext is briefly described, and the access control capabilities that the model provides for hyperdocuments is discussed. The trellis model captures not only the logical relationships among information elements, but also the dynamic properties of a reader´s experience when browsing a document. Using the Petri-net formalism, a hypertext document can be written so that different classes of readers can be allowed or denied access to various portions of the document. The use of browsing restrictions and multiple document versions to implement access classes is discussed. While many of the access capabilities described are not different from those available with graph augmentation techniques, it is believed that the Petri net notation is as intuitively easy to use while being more succinct and convenient