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Re: [Fwd: Negation and Disjunction in RIF]

From: Axel Polleres <axel.polleres@deri.org>
Date: Tue, 20 Nov 2007 16:56:27 +0000
Message-ID: <474311BB.2040905@deri.org>
To: "Public-Rif-Wg (E-mail)" <public-rif-wg@w3.org>
CC: axel@polleres.net

With respect to SWRL, I suggest to extend my previous answer as below:

Axel Polleres wrote:
> I would suggest to answer the following:
> ==========================================================================

Indeed, RIF's Basic Logic dialect (BLD) [1] does not support negation as
failure (NAF). Extensions of rule lanaugages by NAF and other variations
of negation (see [2]) are beyond phase 1 of RIF. The working group
however does at this point not preclude that we will already be starting
to work on dialects which include such extensions in parallel with
finishing Phase 1.

For instance, in the current proposal for a production rule dialect
(PRD), see [3], you will find a construct for negation as failure, which
is currently under discussion, i.e. this draft is not to be considered
as finalized.

Similar considerations apply for disjunction. Note that BLD allows
disjunction in rule bodies, but not in rule heads. Again, later dialects
and the generic extensibility mechanism we are currently working on
shall allow for such extensions.

As for SWRL, note that SWRL is an *extension* of OWL, thus, before 
addressing SWRL completely, we need to address OWL compatibility [4] in 
more detail, which is also work in progress at the moment.

with best regards,

1. http://www.w3.org/TR/2007/WD-rif-bld-20071030
2. http://www.w3.org/2005/rules/wg/wiki/negation
3. http://www.w3.org/2005/rules/wg/wiki/PRdialect
4. http://www.w3.org/TR/2007/WD-rif-rdf-owl-20071030/

> Christian de Sainte Marie wrote:
>> All,
>> The question below was asked on the rif-public-comments mailing list. 
>> anyone cares to draft a reply?
>> Christian
>> ------------------------------------------------------------------------
>> Subject:
>> Negation and Disjunction in RIF
>> From:
>> "Pathak, Jyotishman, Ph.D." <Pathak.Jyotishman@mayo.edu>
>> Date:
>> Wed, 7 Nov 2007 09:52:40 -0600
>> To:
>> <public-rif-comments@w3.org>
>> To:
>> <public-rif-comments@w3.org>
>> Hello everyone,
>> I am a newcomer to this field and trying to learn. The question I have 
>> is w.r.t. support for negation (specifically NAF: negation as failure) 
>> and disjunction in RIF. As far as I know, SWRL natively does not 
>> support them. Is this true for RIF as well?
>> Thank you,
>> - Jyoti

Dr. Axel Polleres
email: axel@polleres.net  url: http://www.polleres.net/
Received on Tuesday, 20 November 2007 16:56:53 UTC

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