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Re: Issue: Add hasValue to OWL Lite

From: Ian Horrocks <horrocks@cs.man.ac.uk>
Date: Wed, 30 Oct 2002 00:34:13 +0000
Message-ID: <15807.10501.554133.349489@merlin.horrocks.net>
To: Deborah McGuinness <dlm@ksl.stanford.edu>
Cc: webont <www-webont-wg@w3.org>

The problem with adding hasValue to OWL Lite is that it wouldn't be
Lite any more. The lack of hasValue in Lite is, from an implementation
point of view, the main thing that differentiates it from fast -
hasValue is very tough to deal with, and is responsible for pushing
the worst case complexity of reasoning in fast OWL from ExpTime to
NExpTime.

Ian

On October 26, Deborah McGuinness writes:
> 
> There have been requests to add hasValue to OWL Lite.  This is a
> proposal to include hasValue in OWL Lite.
> 
> The arguments for adding hasValue include:
> 
> a – It is required for conceptual modeling of common use cases:
> This position is supported by comments sent to public-WebONT-comments
> along with requests in telecoms and face to face meetings.  For example,
> David Jones from Boeing in [1] states that the current OWL Lite support
> their current usage with the primary exception of hasValue.  He states
> that it is required for, among other things, their applications that
> integrate heterogeneous databases.  Others have expressed needs for this
> expressive feature to support other use case scenarios such as
> configuration, b2b commerce, etc.  Claims include that these
> applications can not be modeled without this expressive construct.
> Arguably, it is the most heavily used of the OWL constructs that is not
> in OWL Lite, thus one argument states that if we add anything else to
> OWL Lite, it should be this feature.
> 
> b.  hasValue has been included in some previous description logic-based
> systems and its heavy usage can be seen in applications of those
> systems.  For example, one could look at CLASSIC and Loom applications
> for past evidence of usage.
> 
> c.  It has been proposed by Volz  in [2] that hasValue can be
> implemented on top of standard SQL:99-compatible commercial databases,
> thereby making inclusion in the language less problematic
> 
> The arguments against adding hasValue include:
> 
> d.  OWL Lite is getting somewhat expressive, and there has been
> resistance to adding more features
> 
> e. There has not been a proof of point c above; only some support for
> the position that hasValue does not cause problems for
> implementattions.  There are people who believe that hasValue will cause
> additional complexity for implementers of OWL Lite-compliant systems if
> it is added.
> 
> 
> 
> 
> [1]
> http://lists.w3.org/Archives/Public/public-webont-comments/2002Aug/0014.html
> 
> [2] http://lists.w3.org/Archives/Public/www-webont-wg/2002Oct/0033.html
> 
> 
> --
>  Deborah L. McGuinness
>  Knowledge Systems Laboratory
>  Gates Computer Science Building, 2A Room 241
>  Stanford University, Stanford, CA 94305-9020
>  email: dlm@ksl.stanford.edu
>  URL: http://ksl.stanford.edu/people/dlm
>  (voice) 650 723 9770    (stanford fax) 650 725 5850   (computer fax)
> 801 705 0941
> 
> 
Received on Tuesday, 29 October 2002 19:34:27 GMT

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