- From: Christoph LANGE <ch.lange@jacobs-university.de>
- Date: Thu, 3 Dec 2009 00:21:09 +0100
- To: Semantic Web <semantic-web@w3.org>
- Message-Id: <200912030021.09958.ch.lange@jacobs-university.de>
Dear all, in certain knowledge bases I have encountered metadata inheritance -- one resource A pointing to another resource B, saying "inherit B's metadata". So far, there knowledge bases have not yet assumed an RDF semantics for their metadata, but I'd be interested in changing that. Now I wonder how to appropriately represent this kind of inheritance. In the original application, the metadata of a resource are a fixed record attached to the resource. The metadata are mostly literal-valued (Dublin Core and similar), but some are also URI-valued, pointing to other resources. A naïve approach to inheritance would be a rule { ?resource :inheritsMetadata ?otherResource . ?otherResource ?property ?value . } => { ?resource ?property ?value. } This would, however, easily cause trouble in an RDF world, as 1. the two resources might be of different types, which might be disjoint in an OWL ontology, but what if ?resource inherits rdf:type from ?otherResource ? 2. what if an inherited property is an OWL FunctionalProperty but has different values on ?resource and ?otherResource ? 3. what if the metadata explicitly stated in the scope (e.g. the same XML document) of ?otherResource are fine, but somebody else externally writes a triple ?otherResource :evilProperty "value" ? I consider (3) the most serious problem. A solution might be named graphs. I.e. the metadata that the author of ?otherResource explicitly provided, and that (s)he considers safe, would be put into a named graph G, and the :inheritsMetadata property would not point to ?otherResource but to G. Has that problem ever been dealt with? Is there any publication/specification that you could recommend me to read? Cheers, and thanks in advance, Christoph -- Christoph Lange, Jacobs Univ. Bremen, http://kwarc.info/clange, Skype duke4701
Received on Wednesday, 2 December 2009 23:21:24 UTC