Steve Pepper (Ontopia) recently announced the public release of the TopicMaps.Org Authoring Group Review Specification for XML Topic Maps 1.0. Reference: TopicMaps.Org AG Review Specification 10-Feb-2001. The document has been produced by members of the TopicMaps.Org Authoring Group, with editing by Steve Pepper and Graham Moore. "In the opinion of the Editors, this document represents a complete, stable, and consistent specification of XML Topic Maps, and we hereby offer it for approval by the TopicMaps.Org Authoring Group. TopicMaps.Org is an independent consortium of parties developing the applicability of the topic map paradigm [ISO13250] to the World Wide Web by leveraging the XML family of specifications."
The specification "describes version 1.0 of XML Topic Maps (XTM) 1.0, an abstract model and XML grammar for interchanging Web-based topic maps, written by the members of the TopicMaps.Org Authoring Group. Abstract: "This specification provides a model and grammar for representing the structure of information resources used to define topics, and the associations (relationships) between topics. Names, resources, and relationships are said to be characteristics of abstract subjects, which are called topics. Topics have their characteristics within scopes: i.e., the limited contexts within which the names and resources are regarded as their name, resource, and relationship characteristics. One or more interrelated documents employing this grammar is called a 'topic map'."
An initial document section "Concepts" supplies a clear explanation of "concepts necessary to understand the constructs of XML Topic Maps. The purpose of a topic map is to convey knowledge about resources through a superimposed layer, or map, of the resources. A topic map captures the subjects of which resources speak, and the relationships between subjects, in a way that is implementation-independent. The key concepts in topic maps are topics, associations, and occurrences. A topic is a resource within the computer that stands in for (or 'reifies') some real-world subject. Examples of such subjects might be the play Hamlet, the playwright William Shakespeare, or the 'authorship' relationship. Topics can have names. They can also have occurrences, that is, information resources that are considered to be relevant in some way to their subject. Finally, topics can participate in relationships, called associations, in which they play roles as members. Thus, topics have three kinds of characteristics: names, occurrences, and roles played as members of associations. The assignment of such characteristics is considered to be valid within a certain scope, or context..."
Section 2.1 of the specification provides "A Gentle Introduction to Topic Maps" using an example taken from the domain of electronic encyclopedia publishing: "Let us suppose that we wish to record, in a device-independent and implementation-independent way, the kind of information about the subject matter of a document that might be included in the subject index to an encyclopedia in electronic form. For various subjects -- for example, William Shakespeare, Ben Jonson, their plays Hamlet and Volpone, and the towns of London and Stratford, among thousands of others -- we will wish to record all of the locations in the encyclopedia: (1) whether passages of text, or images, or sound recordings in a multi-media encyclopedia, (2) where they are discussed, depicted, or mentioned. We will speak of these locations as occurrences of these subjects. Note that different occurrences may relate to their subject in very different ways, which we would like to distinguish. In-depth discussions, brief mentions, and illustrations may need to be distinguished in order to allow the users to find more quickly what they need. The encyclopedia we are working with exists in electronic form, so every occurrence of a subject is an electronic resource, for which we can compute an address. They are thus addressable information resources..."
Annexes in the specification provide additional informative and normative information: Annex A: References; Annex B: XTM Conceptual Model; Annex C: XTM Conceptual Model to Interchange Syntax Mapping; Annex D: XTM 1.0 Document Type Declaration; Annex E: XTM 1.0 Core Published Subject Indicators; Annex F: XTM Processing Requirements; Annex G: ISO 13250 to XTM 1.0 Document Transformation; Annex H: Acknowledgements.