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UFDTF Metamodeling Document

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>
Message-ID: <11eb01c831cb$b87cae00$b3200681@MEL.NIST.GOV>


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 GMT

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