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Re: Comments on * DRAFT * Rules Working Group Charter $Revision: 1.60 $

From: Michael Kifer <kifer@cs.sunysb.edu>
Date: Wed, 24 Aug 2005 13:30:52 -0400
To: Jim Hendler <hendler@cs.umd.edu>
Cc: Sandro Hawke <sandro@w3.org>, public-rule-workshop-discuss@w3.org
Message-Id: <20050824173053.A0A7E19E75F@kiferdesk.lmc.cs.sunysb.edu>

> Mike - I've seen a lot of mail from you about what you are against - 
> is there a proposal somewhere that you would suggest we look at as a 
> strawman for a starting place for a rules language compatible with 
> Web architecture?  At least Sandro has tried to specify his strawman. 

Yes. Originally our (WSMO&RuleML) understanding was that the intent was to
start developing a language of rules for the Web, and two months ago we
sent a proposal for a WG charter (to a limited number of W3C people). I am
surprised that you haven't seen it, but I am pretty sure that Sandro
did see it.

Unfortunately, this draft charter proposal was completely ignored, and
there was not even a peep in response.

I am attaching that draft at the end thus making it public.

Now, as it appears that W3C had a somewhat different idea in mind -- an
exchange language -- our charter doesn't quite satisfy that goal. (A Web
rules language is still a very good idea, but these two goals are
complementary.)  This is when I suggested to take a look at RuleML as an
exchange language. I did this because, as I pointed out, the W3C draft
charter has a number of technical problems.

> I've looked at RuleML 0.89 (which I think is latest) - it is an 
> interesting syntax, is there a semantics for it somewhere (I looked 
> on the Web page, but didn't see an obvious candidate) or is the 
> Datalog sublanguage proposed to be the semantics (since it inherits 
> the datalog semantics) - the mission stateent says "The goal of the 
> Rule Markup Initiative is to develop RuleML as the canonical Web 
> language for rules using XML markup, formal semantics, and efficient 
> implementations" which does imply formal semantics are being 
> defined...

RuleML people have realized that there can't be a single super-language
into which everything can be translated with the same semantics. So, their
approach is that the semantics rests with the rules languages and RuleML
defines their XML serializations.

The dream of being able to take any rule-based language, map it into a
"superlanguage", push through the wire, and then map it to a different
rules language at the other end of the wire (with an equivalent semantics)
is a pipe dream - unachievable. At least, not through FOL. So, RuleML takes
a more pragmatic approach.

The only way heterogeneous rule languages can be exchanged as envisioned by
the W3C charter is if we limit the rule sets to those that are equivalent
to Horn rules.  This, IMO, has very limited usefulness.

>   thanks
>   JH
> p.s. I  admit I haven't tracked RuleML for a while and need to get 
> back up to speed, thanks for any pointers that help...

Harold posted the links a day or two ago. The point is, of course, not to
take RuleML literally. But it is obviously good idea to consult with people
who have been thinking about these issues for the past 4-5 years. Instead,
the authors of the W3C charter have completely ignored both RuleML and the
earlier proposed charter draft.


Received on Wednesday, 24 August 2005 17:31:06 UTC

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