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Re: Web Rule Language - WRL vs SWRL

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Thu, 23 Jun 2005 00:54:52 -0400
To: Jim Hendler <hendler@cs.umd.edu>
Cc: Bijan Parsia <bparsia@isr.umd.edu>, www-rdf-rules@w3.org, dreer@fh-furtwangen.de, Jos de Bruijn <jos.debruijn@deri.org>
Message-Id: <20050623045452.2BE31CB5D3@kiferserv.kiferhome.com>


Jim,
So, you are saying that LP is at the same stage as DAML+OIL before
standardization. What is needed is to work out the details -- typically a
job for a working group.  Who disagrees with that?

And you didn't need to defend OWL because nobody was attacking it.  Our
discussion was about the 1-stack vs. multi-stack architectures. Since in a
previous email you said that you are "not against a multi-stack solution"
then I don't see what is the point of contention (at least at the high
level). I believe that everybody agrees that the more integration -- the
better. We just don't believe that integration of the leading useful
technologies to the point that only one stack is left is possible.


	--michael  


> Mike - I think you're missing the point of the "webbie" nature of OWL 
> and the difference from traditional KR, but I have written that up 
> too many times to do it again here.  With LP, the question is how I 
> can use your rules/program/etc. in part to get a "network effect" and 
> to make it so I can link together the logics and logic programs as 
> easily as I link web pages.  It;s not that no one has good research 
> ideas on how to do that, it's how to bring those to fruition and 
> greater use that is the key
>     The ontology stuff in OWL, which is not actually DL (even  OWL DL 
> departs from traditional DL in some interesting ways, but OWL Full is 
> the one I care most about) is based on many years of work in AI, and 
> was explored on the web long before OWL was done - cf the SHOE work 
> my group did (still a high hit at Google - so just google "shoe") and 
> that was followed by XOL, OIL, and others before the standardization 
> began.
>   I think the LP stuff is in similar state - a basic idea has been 
> fleshed out, some variants are being explored, and there is a govt 
> interest in pushing for a de facto standard.   But  going from there 
> to the finish line is where a lot of the time and blood goes in -- 
> it's in making the stuff fit with what else is out there in the Web. 
> We had to do a lot of work to make OWL fit in with RDF and other 
> languages it needed to interoperate with, and a web rules language 
> needs to be defined with the other things already in the space it 
> wants to play in (thus the "stacks" issue - if it wants to be in a 
> Sem Web stack, it needs to play with other SW stuff; if it wants to 
> be in the XML stack, it needs to play nice with XML stuff like Xquery 
> and Xpath, etc.
>   And that is the discussion we are having -- but if we can nail this 
> stuff, the result is worth it -- OWL is certainly the most used 
> KR/ontology langauge in the history of AI as best anyone can tell, 
> and if we want the Web Rules Language to flourish we want it to grow 
> like the Web does, not like rules languages have -- nothing wrong 
> with the latter, but there's a whole lot more Web pages out there 
> than logic programs, and it's a lot more fun to play in the 
> exponential growth space :-)
>   anyway, we're all working for same ends, just different means, and 
> finding the consensus space in the middle is wondefully non-fun, but 
> worth it in the end
> 
>   Ok, end of crap, back to technical issues and Greek symbols...
>   JH
> p.s. please note - I spent many years of my career arguing against DL 
> and doing scruffy AI - yet here I am defending OWL - why?  because 
> the design time and fights over the details of a number of use cases 
> ended up creating something pretty damn useful -- both in the OWL DL 
> space and in the OWL Full space -- so somehow the process worked...
> 
> 
> At 20:41 -0400 6/22/05, Michael Kifer wrote:
> >Jim Hendler wrote:
> >>
> >>  Mike - I think you misunderstand the stuff about stacks and etc -- I
> >>  hope my use cases (in public-sws-ig@w3.org for those just joining the
> >>  conversation) would help make it clear that these are not separate
> >>  and unrelated stacks, nor are they identical things -- the key is
> >>  figuring out how the stacking works and how things interact -- I'm
> >>  not against a "multi-stack: solution, but as far as I am concerned
> >>  the more overlap the better, and I am fairly sure that we can do
> >>  significantly better than DLP in terms of providing a useful web
> >>  rules language that interacts well with the existing, and becoming
> >>  more widely used, ontology spec.*
> >
> >I think it is not just me, but a number of people who read your paper on
> >the two stacks may have misunderstood it. At least one way to understand
> >what is said there is that 1 stack is good and 2 is not.
> >If there is another way to understand it (as advocating a multi-stack
> >architecture) then this second meaning is deeper than I was able to dig up.
> >
> >>    Seems to me the key is exploring how to get maximum interoperability
> >>  between the important work in BOTH areas (and I defy you to go back
> >>  through this discussion and find any email where I haven't said I'm
> >>  in favor of a web rules language)
> >
> >You didn't say this and I didn't say that you said this.  I was
> >focusing on what I think were technically inaccurate claims in your email
> >regarding the layering of WRL on top of DLP (where WRL is taken to mean the
> >particular language under this name and not "a" generic web rules language).
> >
> >>  and also how to get the Web rules
> >>  to join in the growing whole that is the semantic web -- it's not the
> >>  same as applying LP in the Web area -- I argued for nearly a decade
> >>  about the difference between Web Ontology and standard AI KR
> >>  languages, and OWL has some significant differences from traditional
> >>  AI (see the OWL FAQ [1] and the discussion of KR  back in the 2001
> >>  Scientific American article [2])
> >
> >Not "applying LP in the Web area" but "adapting LP to the Web".
> >Technically, OWL is an adaptation of DL to the Web with some additional
> >research needed to accommodate RDFS.  But in the LP area this research has
> >already been done years ago.
> >
> >>  This latter, btw, explains why URIs
> >>  are not just some wildassed thing, they're crucial to the Semantic
> >>  Web in a very deep way - read the Sci Am or any of Tim's discussions
> >>  of this issue.
> >
> >Of course URIs are crucial. After all, they are object identifiers, so they
> >are as crucial as any notion of an Id.
> >
> >But do they imply/require a new kind of KR?  There are interesting new
> >problems that stem from the architecture, but don't make it sound as if the
> >"old KR" is out of the window and adapting it to the new architecture is a
> >hard or pointless exercise. The LP paradigm is as applicable to the Web as
> >DL, if not more. (I, of course, think that it is more :-)
> >
> >
> >>    so, I don't see this as in any way being a discussion of rules vs.
> >>  ontology -- in fact, I cannot think of any dumber way to approach it
> >>  -- rather it seems to me we're trying to explore where these things
> >>  can overlap to the benefit of users and of the Web -- that strikes me
> >>  as a very worthwhile pursuit
> >
> >The term "rules" is ambiguous in the context of our discussion. If you said
> >"I don't see this as in any way being a discussion of *LP* vs. ontology"
> >then this is exactly what I was trying to say. As I remarked above,
> >the 2tower paper **appears** to be arguing that LP+OWL in a 2-stack
> >architecture is a nonstarter.
> >
> >
> >	--michael
> >
> >
> >>    -JH
> >>
> >>
> >>  [1] http://www.w3.org/2003/08/owlfaq.html
> >>  [2]
> >> 
> >>http://www.sciam.com/article.cfm?articleID=00048144-10D2-1C70-84A9809EC588EF21
> 
> -- 
> Professor James Hendler			  Director
> Joint Institute for Knowledge Discovery	  	  301-405-2696
> UMIACS, Univ of Maryland			  301-314-9734 (Fax)
> College Park, MD 20742	 		  http://www.cs.umd.edu/users/hendler
> 
Received on Thursday, 23 June 2005 04:56:33 GMT

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