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Re: DOCUMENT: Layering document review (was Re: UPDATE: status of longer version of layering document)

From: Jim Hendler <hendler@cs.umd.edu>
Date: Wed, 13 Feb 2002 13:26:28 -0500
Message-Id: <p05101404b8905edc1bec@[]>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: www-webont-wg@w3.org
At 12:54 PM -0500 2/13/02, Peter F. Patel-Schneider wrote:
>From: Jim Hendler <hendler@cs.umd.edu>
>Subject: Re: DOCUMENT: Layering document review (was Re: UPDATE: 
>status of     longer version of layering document)
>Date: Wed, 13 Feb 2002 09:39:03 -0500
>>  Frank - the problem is that 1-4 as you define them below are
>>  APPROACHES, not yet proposed solutions to move on.  I mean we need to
>>  figure out how we operationalize these approaches and move to
>>  language features that support them.
>Well, I believe that there already are proposed solutions using approaches
>2, 3, and 4.
>Approach	Proposal
>2.Syntax and semantic extension
>OWL - 
>3.Same-syntax, but diverging semantics
>DAML+OIL - http://www.w3.org/TR/daml+oil-reference
>4.Differing syntax and semantics
>OWL' - 

(Bad URI, please check)

>What more do you want before having a discussion of which approach to work

The only one of these currently in a form the WG could actually take 
action is the 2nd, since it is in the form we need to get to and the 
charter says we should use it as a point of departute.  The others 
are still primarily in the form of theoretical contributions, and 
would need work to become actual langauge standards, which is what we 
are producing -- i.e. they need to come out like the second.  These 
are good places to start discussion, but they aren't completed and 
need work - all I'm trying to work out.

>You may note that each of these approaches have (roughly) the same language
>features.  In general, the characteristics of the language do *not* depend
>on which approach is taken.  (Of course, the syntax details of the language
>and the formal specification of the language *do* depend on which approach
>is taken, but both of these can be largely ignored when discussing which
>approach to take.)
>>  It is fine and good for the group to decide "We will have a XXX
>>  syntax and YYY semantic extension" (or whatever), but that doesn't
>>  say which things will be the same or different from current DAML+OIL
>>  or why.  We clearly need to set philosophy as part of moving ahead,
>>  but the "task force" I suggested yesterday will need to go through
>>  D+O figuring out how we change it, if at all, to deal with the issues
>>  we've been discussing -- I'm trying to be hard-nosed here and remind
>>  everyone that we need to eventually get this all the way to language
>  > features.
>>    To date, I see nothing that specific on the table, and we need such.
>Well, if the two documents I put together were not specific, then I don't
>know what you want.

ahh, i see the problem from the above -- the SYNTAX details are 
critical to the W3C standard we are trying to work out - they're not 
a minor detail to leave up to the implementors.

>>  For example - a differing syntax solution could be anything from
>>  "chuck the entire DAML+OIL and start again from scratch using C++
>>  syntax" to "if we simply add the tag <OWL></OWL> around the OWL
>>  equivalent of daml:class statements then everything works again"  --
>>  that's quite a range!  Also, it is complicated by the fact that some
>>  of our reasoning may need to go like this:
>>    If RDF were changed to allow XXX then our language works as is (or
>>  with the following minor modification)
>>    if not, then we need to drastically change our language to YYY (for
>>  example, largely abandoning RDF syntax)
>>  which is the best way we could be able to communicate this sort of
>>  thing back to an RDF WG (either Core or future RDF 2.0) for
>>  consideration or joint solution.
>It would, I suppose, be possible to state some changes to RDF(S) under
>which each of the approaches could be considered to be an extension of

We cannot state changes to RDF(S) (another group's work product), but 
we can recommend such and discuss with those groups to reach some 
sort of joint consensus.

Professor James Hendler				  hendler@cs.umd.edu
Director, Semantic Web and Agent Technologies	  301-405-2696
Maryland Information and Network Dynamics Lab.	  301-405-6707 (Fax)
AV Williams Building, Univ of Maryland		  College Park, MD 20742
Received on Wednesday, 13 February 2002 13:26:39 UTC

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