- From: Conrad Bock <conrad.bock@nist.gov>
- Date: Wed, 28 Nov 2007 09:34:02 -0500
- To: "'Web Ontology Language \(\(OWL\)\) Working Group WG'" <public-owl-wg@w3.org>
UFDTF, Some comments about metamodeling in the user-facing documents: - I would expect the draft metamodel document (http://www.w3.org/2007/OWL/wiki/MOF-Based_Metamodel) is part of the user-facing documents, at a similar level and audience as the reference manual. It's important that this and the OMG's Ontology Definition Metamodel for OWL are aligned, because OMG is perceived as the primary source for MOF-based metamodels. - We should also review and clarify the statement about metamodeling in the submitted overview: In OWL 1.1 a name (such as Person) can be used as any or all of an individual, a class, or a property. The computational problems that would arise if this were treated as in RDF are avoided by ensuring that no aspect of the use of the name as an individual has any effect on the meaning of the name as a class. Such a treatment of metamodeling is often called punning. Even with no metamodeling, the use of a name as an instance of owl:class and as the type for an individual are of course related. For example, if M1:car is an instance of owl:Class, it is also the type for M0:johns-car. This is also true for metamodeling, see next. - Finally, we should address a common use of metamodeling that extends OWL for modeling languages. This defines subclasses of owl:Class with additional properties that have values on the instances of the subclass. For example, uml:Class as a subtype owl:Class would add characteristics of classes peculiar to UML, such as isAbstract. This does not imply any DL reasoning on owl:class its subtypes (these are only used to type instances, which are only created, read/queried, modified, and deleted), or introduce any constraints that would affect DL reasoning on the instances of instances of owl:class. Some earlier discussion of metamodeling in OWL is at http://www.w3.org/2007/OWL/wiki/index.php?title=OWLMetamodeling. Conrad
Received on Wednesday, 28 November 2007 14:34:21 UTC