RE: [RIF] [UCR]: What is the RIF (revisited) --> disjunctive conclusions

Another way of looking at this / let me infer: the commercial inference
engines that do not support "disjunctive conclusions" prove, by the fact
of their use in commerce, that this feature is not a requirement for
rule use, and is therefore not a requirement for rule interchange. 

There may be applications and engines that require it - Perhaps someone
could point out the use cases, hopefully commercial, that require this
feature?

 

And then hopefully someone will explain what it means... :-) 

 

[I see from
http://lists.w3.org/Archives/Public/public-rif-wg/2005Dec/0045.html the
rule 

"every student with major in Computer Science must have a minor in
Mathematics or in Physics"
But in an operational s/w system this could be viewed as a constraint,
but what is there to infer?]

 

 

Paul Vincent

Fair Isaac Blaze Advisor --- Business Rule Management

OMG Standards for Business Rules, PRR & BPMI

mobile: +44 (0)781 493 7229 ... office: +44 (0)20 7871 7229 

 

 

-----Original Message-----
From: public-rif-wg-request@w3.org [mailto:public-rif-wg-request@w3.org]
On Behalf Of Piero A. Bonatti



On Wednesday 08 February 2006 17:13, Dieter Fensel wrote:

> >But OWL/SWRL have already introduced disjunctive

> >conclusions (which btw are not a problem for the

> >model-theoretic semantics, even not when combined

> >with NAF; they are only a problem for the inference

> >engines), so this is not PhD research!

> 

> 1) They are ONLY a problem for the inference engines!!!!!!!!!

> So for the ONLY thing that really counts.

 

there are very interesting inference engines - notably, DLV - based on 

disjunctive logic programming (i.e. they support disjunctions in the
head).  

they are nicely and efficiently integrated with widespread databases and
have 

already attracted the attention of some companies

 

and there will be more and more engines supporting more and more useful 

features, as time goes by.

 

so why should a rule INTERCHANGE format exclude the features supported
by such 

engines?

 

in general, WHATEVER FEATURE WE EXCLUDE A PRIORI IS A POSSIBLE CAUSE OF
EARLY 

OBSOLENCE OF THE RIF STANDARD

 

I don't see why interoperability should be guaranteed among arbitrary
pairs of 

reasoning systems.  one can't plug a PCMCIA device into a USB port.  

similarly, the RIF should allow 

 

- disjunctive engines to interoperate with each other

- "minimalistic" rule engines to interoperate with each other

- disjunctive and "minimalistic" rule engines to interoperate, *when the


shared rulebase is simple enough*

 

but of course an engine is not obliged to understand or make sense of
every 

possible rule encoded in the RIF

 

what I would really expect from RIF is support for fast and effective 

identification of the features actually used by a rulebase, so that an
engine 

can quickly check whether it can interpret those rules.  here all sorts
of 

properties may come in (range restrictions, hierarchic or recursive
rulebase 

structure, datalog or function-supporting fragments, etc.).  the
metadata 

attached to a rule encoding would more or less directly specify the 

requirements on the inference engine

 

this approach yields a far more scalable standard

 

piero