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Re: CR/PR questions

From: Jeremy Carroll <jjc@hpl.hp.com>
Date: Mon, 5 May 2003 23:18:29 +0300
To: www-webont-wg@w3.org
Message-Id: <200305052318.29865.jjc@hpl.hp.com>

> Would you argue there isn't enough evidence for 
> Prolog to move to PR if we were the Prolog WG?

There are some standard execution models for Prolog.
So if my chess program terminates in a month on swi-pl I would be surprised if 
it takes 300 years on yap.

Admittedly there are some variant execution models but those that are likely 
to impact whether your program works at all are usually prominently 
contrasted with the standard implementation (Warren Abstract Machine).

===

So, agrreing that P !+ NP, we see that even OWL Lite is at some level 
problematic ... and I haven't expressed anxiety about that. What's the 
difference?

I think that the type of constructs one needs to use in Lite to get to encode 
computationally hard problems are really quite unnatural, i.e. I think they 
are of theoretical interest but not ones that real data are likely to 
exhibit.

On the other hand, the feature interactions in OWL DL that cause the problems 
seem, in my judgement, to be ones that happen quite naturally.

Given the ability to make closed world comments about the cardinality of 
properties then it seems natural to say a property is N-to-M. Given three of 
these connecting three finite or infinite classes then you get the test cases 
I have just posted. This does not feel to me like an academic game, but a 
serious engineering point - if we don't expect the users to use such 
facilities we probably should not define them.

My triangle pictures - at least for me, it is natural to describe them to 
highlight certain points - their triangularity and their vennness. These 
descriptions are topolgocial and can be encoded in OWL DL, yet reasoning with 
them involves working out who is who, with the absence of unique names. (The 
3-SAT examples are artificial problems steming from the absence of unique 
names).

More another day ...

Jeremy
Received on Monday, 5 May 2003 17:18:21 GMT

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