W3C home > Mailing lists > Public > www-rdf-interest@w3.org > December 2001

RE: Cutting the Patrician datatype knot

From: Pat Hayes <phayes@ai.uwf.edu>
Date: Tue, 4 Dec 2001 00:02:10 -0600
Message-Id: <p0510100eb832156171da@[169.254.199.144]>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: www-rdf-interest@w3.org, joint-committee@daml.org
>From: Pat Hayes <phayes@ai.uwf.edu>
>Subject: RE: Cutting the Patrician datatype knot
>Date: Thu, 29 Nov 2001 17:40:02 -0600
>
>[...]
>
>>  OK, but now what is the problem with my MT extension, again? Of
>>  course, with THIS sense of "union", one cannot treat [integer union
>>  string] as in any sense the simple class-union of the classes
>>  [integer] and [string]. So as far as the RDF reasoner is concerned,
>>  [integer union string] is just another datatype, which might as well
>>  be called [foodle]. If someone were to assert that
>>
>>  [integer] rdfs:subClassOf [integer union string] .
>>
>>  that would be correct, but that would cause no problem in the MT,
>>  since [integer union string] agrees with [integer] on numerals; they
>>  have the same lexical-to-value mapping on anything that would map to
>>  an integer. Similarly, it would be correct to assert
>>
>>  [string] rdfs:subClassOf [string union integer] .
>>
>>  though in that case it seems rather pointless since in this case the
>>  datatypes are identical, since even numerals will be mapped as
>>  strings by that union. But again, this poses no problems for the MT.
>>  On the other hand, if someone were to assert
>>
>>  [string] rdfs:subClassOf [integer union string] .
>>
>>  then that would be simply false, as all numeral strings are in the
>>  former value space but not the latter.
>
>I don't see how this follows.  The value space of the XML Schema datatype
>[integer union string] is precisely the union of the value spaces of
>integer and string.

Yes, Ive come to see that. I simply did not conceive that anything 
could be this badly defined. This aspect of XML datatypes really is a 
crock. It *defines* the domain and range of the datatyping functions 
so that they cannot possibly be the real domains and ranges. What a 
bloody silly thing to do, I'm amazed that Thompson put his name on it.

So, my argument does not hold if we are obliged to conform to XML 
datatyping rules. I am inclined to just give up and leave this 
decision to others, at this point. There is no point trying to be 
rational when one is obliged by mandate to conform to irrationality. 
Let me know what y'all decide.

Pat


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Received on Tuesday, 4 December 2001 01:01:12 GMT

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