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Re: issue 5.10: a position statement (sameState over peopleKey)

From: Dan Connolly <connolly@w3.org>
Date: 18 Jul 2002 16:21:03 -0500
To: Jim Hendler <hendler@cs.umd.edu>
Cc: "Peter F. "Patel-Schneider <pfps@research.bell-labs.com>, www-webont-wg@w3.org
Message-Id: <1027027264.27663.399.camel@dirk>

On Thu, 2002-07-18 at 16:03, Jim Hendler wrote:
> Dan - I'm confused as to the import of the peopleKey example - have 
> looked at the rdf (btw, there's a small bug - you use "oneto99" 
> instead of "oneto9" at one point)

ah; quite. thx.

>  - you are going to pick a member 
> of your family and assign them a key from that range.

Well, that's sort of a procedural way of looking at it.

I've said each person has a unique ID. (oops; actually,
I haven't said that... but I meant that...). And
that unique ids are numbers from 0 to 9, and
that persons with the same uniqueID are the same person.

>  Since there 
> are potentially more than 10 family members,

There are *actually* more than 10 family members;
there are 11 different name-strings, and
since giveName is functional, different name-strings
mean different people.

> there will be someone 
> who cannot be assigned a range

yup. Contradiction.

> - but it seems you're asking the 
> system to recognize a logical inconsistency at a "definitional" level 
> that doesn't occur until you try to use them -- that is, you haven't 
> said everyone of these people will be assigned a key.

Yup. Good catch.

I meant to say
	Person hasAtLeastOne uniqueId
as well as
	uniqueId a UnambiguousProperty.

>  So it seems to 
> me that until the 11th time you ask for this to be used,

There's that procedural phrasing again... the contradiction
is there, regardless of when the system notices it.

> the system 
> is fine -- and there's no way for the system to read your ontology 
> definitions and know for sure that you will eventually ask for all 
> these people (maybe you're just picking names for your future kids 
> and if you end up never having that 11th, you'll never get in 
> trouble).
>   It would be nice to have validators that could say things like "I 
> notice you only are assigning ten keys to a list that could 
> potentially eventually have an 11th element, so please be careful" 
> but I'm not convinced there really is a logical inconsistency in such 
> a definition.

There was a bug in the test case.

I hope that it's clear that given Person hasAtLeastOne uniqueId,
this is a contradiction.

>   This is a long-winded way of saying I find being able to do the 
> state stuff more compelling than the potential personkey problem...
>   -JH

-- 
Dan Connolly, W3C http://www.w3.org/People/Connolly/
Received on Thursday, 18 July 2002 17:21:04 GMT

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