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Re: [closed] issue #pfps-10 untyped literals

From: pat hayes <phayes@ai.uwf.edu>
Date: Thu, 1 May 2003 10:52:31 -0500
Message-Id: <p05210628bad6e8ec9635@[]>
To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: www-rdf-comments@w3.org
>From: pat hayes <phayes@ai.uwf.edu>
>Subject: [closed] issue #pfps-10 untyped literals
>Date: Tue, 29 Apr 2003 16:12:28 -0500
>>  Peter,
>>  In
>>  http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0085.html
>>  you raised a last call comment on the RDFCore WD's which was recorded as:
>>  http://www.w3.org/2001/sw/RDFCore/20030123-issues/#pfps-10
>>  The RDFCore WG has accepted your comment:
>>    http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Apr/0361.html
>>  and the current editor's draft of the semantics document
>  > http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-mt-20030117/
>>  now requires that LV is exactly the class extension of I(rdf:Literal)
>>  in all RDFS interpretations, and the entailment you mention
>>  incorporated into the proof rules.
>>  Please reply to this message, copying www-rdf-comments@w3.org,
>>  indicating whether this decision is acceptable.
>>  Pat Hayes
>This message is somewhat better than the previous one, but it is still
>rather difficult to find out just what is going on here.  Pointing to the
>appropriate change(s) in the document would help somewhat.

The document begins with a table of changes made since last call, 
with commentaries and links to the text. The text linked to this 
issue reads as follows:

The treatment of literal values has been technically improved 
somewhat.             This involves several changes to the text in 
several places but in sum, the net effect is that the class 
rdfs:Literal is now identified with the set of all literal values  in 
all interpretations , and that the treatment of untyped literals is 
now exactly aligned with typed literals .  In fact, it is possible to 
think of untyped literals as typed with  a trivial 'invisible' 
datatype in which the lexical and value spaces are identical and the 
L2V mapping is the identity.[ This has been added as a comment here ; 
this addition is   tentative and could be omitted; feedback welcomed 
.]  These changes make the overall design of the semantics slightly 
more  conventional and also more coherent. They also support 
entailments  which members of the WG feel are correct, in particular 
the RDFS entailment

aaa ppp "sss" .
aaa ppp _:x .
_;x rdf:type rdfs:Literal .

It is not practical, and I do not think it would be useful, to give a 
detailed list of every textual change made as a result of this 

The most important change was IEXT(I(rdfs:Literal)) now = LV , rather 
than being a subset of LV 
; in addition, LV is now considered to be one of the domains defined 
by an interpretation, instead of a 'global' domain; although there 
are a number of conditions on LV in any interpretation. (The exact 
description of the XML-related items in LV listed in the table in 
http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-mt-20030117/#interp is 
known to be wrong, by the way, and will be corrected once the 
treatment of XML literal values is stable.)

The entailment referred to above is now listed as closure rule rdfs1 

There were a number of textual changes made, particularly in the 
introductory material in section 1, to avoid giving what would now be 
a misleading impression of the intuitive meaning of LV.

>Peter F. Patel-Schneider
>Bell Labs Researchout i
>Lucent Technologies
>PS: Many of my issues with the RDF semantics were known to the RDF Core
>Working Group before going into last call.

I believe it might be fair to say that they were not all fully 
understood by the WG before last call, however.

>  In my opinion it would
>therefore be a very good idea to ensure that all issues with the RDF
>semantics and their resolutions have detailed documentation in

I take it then (and because I know that you know the detailed answers 
already) that your request to have things spelled out in these 
messages is not in order to enable you to respond, but because of 
your views on the proper procedures to be adopted by the RDF WG.

My understanding was, and is, that the purpose of these rather formal 
messages is to put on public record the fact that your question has 
been addressed, and your response to it. If you disagree with this, I 
suggest that you raise that issue with the WG chair.  In the 
meantime, however, I would be grateful for your reply to the actual 
response, independently of your views on proper procedure.


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Received on Thursday, 1 May 2003 11:52:36 UTC

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