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Re: how to proceed with building OWL [was Re: semantics: layering ...]

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Fri, 01 Mar 2002 10:48:53 -0500
To: hendler@cs.umd.edu
Cc: www-webont-wg@w3.org
Message-Id: <20020301104853T.pfps@research.bell-labs.com>
From: Jim Hendler <hendler@cs.umd.edu>
Subject: Re: how to proceed with building OWL [was Re: semantics: layering ...]
Date: Fri, 1 Mar 2002 10:22:35 -0500

> At 8:00 AM -0500 3/1/02, Peter F. Patel-Schneider wrote:
> >	Constructing Web Ontology Languages
> >				or
> >	Why Jumping on Four Horses is a Good Recipe for Quartering
> 
> 
> 
> Peter- I think I agree with everything you said in your message, 
> except the overall implication that somehow layering drives the whole 
> process.  It is a necessary player, but it seems to me the language 
> functionality, driven by the work we've been doing in use cases and 
> reqs could also be put up as the main driver.  here's my argument
> 
> 
> 1) Let's assume the group decided that RDFS was the perfect ontology 
> language and needed no new language features.  In this case, layering 
> with RDFS is perfect and the problem goes away
> 
> 2) Let's assume the group decided the entire DAML+OIL functionality, 
> plus more is what we want.  In this case, the layering issue, and how 
> we deal with it, becomes important.
> 
> So somewhere in the middle between no new features and lots of new 
> features will be language designs that are perfectly compatible (i.e. 
> no paradoxes), that are not as compatible (i.e. paradoxes abound) and 
> that are "fixably compatible" (i.e. w/some trade-offs we could manage 
> to get a language people like with no major paradoxical situation)
> 
> Seems to me, therefore, that until some strawman language proposals 
> come along, and Frank has agreed to start this process, there is no 
> way we can discuss the specifics of layering -- we can discuss the 
> philosophy of how we see languages fitting together (and your 
> document was a great start on that discussion), and we can discuss 
> practical implications with respect to syntax once we have some 
> proposed language features to "test" them against.

I worry that a strawman proposal that is not well within our capabilities
to define correctly will end up consuming a lot of time and effort as those
of us who worry about how to formally define the language try to convine
the others that they are asking for too much.  That is why I would much
prefer some common understanding of what is easy (i.e., has been done),
what is possible (i.e., doesn't seem to cause any problems), what is
difficult (i.e., needs real work to create), and what is impossible (i.e.,
causes paradoxes) before a strawman is created.

Now maybe Frank will come up with a strawman proposal that is easy, in
which case there not be too many problems.  However, I'm not counting on
it.

[...]

> At 8:00 AM -0500 3/1/02, Peter F. Patel-Schneider wrote:
> >
> >1/ Some of the basic notions of OWL are determined, such as the general way
> >    its syntax is going to look and how it layers on top of RDF(S).
> 
> but trying to do this not anchored from language features seems odd 
> to me at this point in the process - making an a priori decision 
> w/respect to the layering without now taking a stab at defining what 
> we'd LIKE to accomplish is just as wrong as would be taking that stab 
> without having been informed by the document on layering would have 
> been.

Well this initial phase could indeed determine some of the features of OWL,
such as that it has defined classes or properties, etc., without going into
details.

> In short, I see a chicken and an egg here, and the only way I've ever 
> seen chicken and egg problems cracked is to role up ones sleeves, get 
> some stuff on the table from multiple perspectives, and then work to 
> reconcile the views - and that's what I'm thinking we need to do 
> here.  In fact, that's how the Joint Committee that created DAML+OIL 
> was formed and worked, and it seems to have worked out pretty well in 
> the end...

[...]

I worry that the WG is going to spend time on the strawman, only to find
out that a lot of it has to be redone.  Besides which, don't we have several
strawmen already?

peter
Received on Friday, 1 March 2002 10:49:43 GMT

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