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

On Wednesday 08 February 2006 18:20, Vincent, Paul D wrote:
> 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.

the use in commerce is never equal to affordable technology. cobol has been 
used for far longer than it should have, and better approaches were delayed 
(at the cost of several expensive failures) precisely because many people 
forget that current commercial applications are not the state of the art, but 
rather the state of the market...

production rules are the cobol of decision support systems and semantic web.  
surely in the area of trust management those who built systems based on RETE 
had quite bad results compared to other approaches

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

I understand that your organization's business has to do with decision support 
systems in financial applications.  so you may appreciate the following 
example.  company C wants to sell part of the companies it controls.  the 
constraints are: (i) after the transaction, C should still be able to produce 
whatever it cares to produce; (ii) companies should actually be sold, i.e. C 
should not control them anymore after the transaction

you *need* disjunctions in the head to encode this problem - without this 
feature the encoding is exponential. still the problem is of natural interest 
and it would be nice to solve it with a rulebase

more generally, problems that admit multiple solution - to be chosen by a 
human - benefit from some extension (disjunctions or alternative, equivalent 
stuff).  if you want your system to suggest the alternatives, possibly ranked 
with a preference value, then you're often going to have a hard time with 
production rules, that are biased towards determinism (even priorities don't 
help much in that case)

another example is data integration, especially the (extremely interesting!) 
"local as view" approach - see for example the INFOMIX effort 
(http://www.mat.unical.it/infomix).  again, with production rules you'd have 
a hard time...

Dieter says this is still food for PhD students.  I don't agree - these ideas 
are closer to pre-competitive solutions than some companies would like to 
admit.  so I have to insist that a standard that can't handle this kind of 
extra features is likely to become obsolete earlier than expected

moreover, I don't see why crafting a syntax and a meaning for richer rules 
such as disjunctive rules should complicate RIF's task so much.  so what is 
the real reason for keeping them out of the RIF?

piero

Received on Thursday, 9 February 2006 09:03:12 UTC