W3C home > Mailing lists > Public > public-rif-wg@w3.org > March 2006

RE: [UCR] RIF needs different reasoning methods

From: Gerd Wagner <wagnerg@tu-cottbus.de>
Date: Mon, 6 Mar 2006 22:08:50 +0100
To: "'Francois Bry'" <bry@ifi.lmu.de>, "'Bijan Parsia'" <bparsia@isr.umd.edu>
Cc: <public-rif-wg@w3.org>
Message-ID: <000301c64162$2f39dec0$17d52b8d@TMGWAGNER>

> >> The following is a (sketch of an) application scenario illustrating
> >> different forms of reasoning with rulesets that, in my opinion, the
> >> RIF should support.
> >
> > What is the nature of that support? I mean, pragmatically speaking,
> > what needs to be done to enable such support?
>
> To make it possible to distinguish between different fragment of RIF:
> 
> 1. declatratibe RIF rules, themselvbes distinguished into 1.1 
> deduction rules and 1.2 normative rules
> 2. reactive rules

In addition, similar to the general software issue of exception 
handling, we may want to be able to indicate how to proceed
in the case of inconsistencies in a RIF rule set, when the 
standard FOL semantics fails to provide any reasonable 
prescrption of what to do.

> > Isn't resolution a refutation technique? Did you mean 
> > something stronger?
>
> REsolution (including SL resolution) are refuytartion methods. SLD
> resolution is not - in spite of a common belief.

Francois is pointing to the fact that SLD resolution corresponds 
"isomorphically" to constructive inference based on Modus Ponens.
Therefore, it's not really refutation-based.

> >> Note that existing OWL reasoners only address 2 above. They can
> >> perform 1 but at unnecessary costs.
> >
> > Er...not necessarily. KAON2? Actually, regular tableaux based
> > reasoners can do pretty well, depending. (Granted, they do not
> > typically use secondary storage, but they can do quite well.)

I doubt that we can already conclusively judge what OWL/SWRL reasoners
can and what they cannot. We do net yet have sufficient (theoretical 
and practical) experience with them, as opposed to logic programming
inference engines, about which we know much more.

-Gerd

--------------------------------------------
Gerd Wagner 
Brandenburg University of Technology 
at Cottbus, Germany
http://oxygen.informatik.tu-cottbus.de/IT
Tel: 0355-69-2397
Email: G.Wagner@tu-cottbus.de
 
Received on Monday, 6 March 2006 21:12:12 GMT

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