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Re: WOWG: first language proposal

From: Deborah McGuinness <dlm@KSL.Stanford.EDU>
Date: Wed, 27 Mar 2002 18:25:11 -0800
Message-ID: <3CA27F07.49FBCCCC@ksl.stanford.edu>
To: Frank van Harmelen <Frank.van.Harmelen@cs.vu.nl>
CC: www-webont-wg@w3.org
Thanks for your work on the proposal.
I have been offline but am back now and am making comments on the proposal.

I totally support the motivation of getting the frame-like qualities back in the
language and am mostly in agreement with the first sketch
http://www.cs.vu.nl/~frankh/spool/OWL-first-sketch.html

Although I would make some tweaks.
One general question is how did things end up in point 2 – the frame-part
Vs. point 3 – the axiomatic part?

I would like for one motivation for the distinction to be to include the portions
in the frame part that are expected to be used routinely by the general public.
I would claim a secondary motivation is to attempt to include the “standard”
notions in the “average” frame system in this class.

If you buy into this motivation, then I think we should include value restrictions
in the frame part.  I would also consider putting non qualified number
restrictions in this portion.   I have analyzed a lot of dl knowledge bases as
well as a lot of frame knowledge bases (in particular in classic, assorted other
dl kbs, okbc, ontolingua, snark, etc.) and find that value restrictions and at
least min cardinality 1 and quite often max cardinality show
up with great frequency.

If we keep this mentality, it is not clear that inverse, transitivity, and
disjointness must stay in the frame part although it would be my preference to
keep them there.

In http://www.cs.vu.nl/~frankh/spool/OWL-first-proposal/motivation.html
Some cardinality is reintroduced which I support.
The proposal would allow min card 1 & max card 1 but would NOT allow mincard 1 and
max card 2 in the frame portion.
I think it is a common frame notion to include this second thing and it is also a
common frame representive issue to allow exactly 2 values.
I do not require this in the light frame portion but I would like not to make
people go over to the axiom portion to state this.

I also support that
http://www.cs.vu.nl/~frankh/spool/OWL-first-proposal/motivation.html
includes local range of property.  I think this is critically important to have in
the “easier frame portion”   and my reading of the first sketch did not allow it.

I am not in support of only 2 parts – the very light frame part and the axiom
part.
I am in support of 3 parts
– the light frame part,
- the more comprehensive frame part  (including things like max cardinality or
exact cardinality other than single-valued)
- the axiom part.

If people agree with this breakdown.  I am willing pick up joint editing
responsibility of the language proposal with the new break down.

 If you prefer no additional editors but like the proposal, I am willing to do a
separate phone discussion or provide separate input to generate the next round.

deborah

Frank van Harmelen wrote:

> As per our action item from March 7, we have prepared a first language
> proposal, for discussion in this weeks teleconf, and as the basis for further
> work by the language focus group.
>
> At http://www.cs.vu.nl/~frankh/spool/OWL-first-proposal/
> you will find three documents:
>
> - A short motivation of our design and choices (2pgs)
> - An annotated example to give you the flavour (walkthrough) (5pgs)
> - The language definition as a simple grammar (5pgs)
>
> We suggest you read the documents in this order.
>
> EXECUTIVE SUMMARY:
>
> Our proposal for the OWL Knowledge Base Language comes in two parts:
>
> 1. The first ("light") part is loosely based on the frame idiom found in the
> frame-style systems that have been used in AI for decades. This idiom has been
> extended with commonly found ontology modelling idioms and a number of
> features that are important in the Web context.
> This "light" version will provide a lower entry threshold to the language,
> while still providing much of the required expressiveness.
>
> 2. The second ("full") part is very close DAML+OIL.
>
> Peter Patel-Schneider,
> Ian Horrocks
> Frank van Harmelen.
>     ----

--
 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/index.html
 (voice) 650 723 9770    (stanford fax) 650 725 5850   (computer fax)  801 705
0941
Received on Wednesday, 27 March 2002 21:26:00 GMT

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