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Re: Proposal for adding new datatypes from XSD 1.1 (ISSUE-66)

From: Pat Hayes <phayes@ihmc.us>
Date: Wed, 2 May 2012 13:14:23 -0500
Cc: Richard Cyganiak <richard@cyganiak.de>, "Peter F. Patel-Schneider" <pfpschneider@gmail.com>
Message-Id: <68054A9A-D217-4FBA-B092-87868C569AF3@ihmc.us>
To: RDF Working Group WG <public-rdf-wg@w3.org>

On May 2, 2012, at 4:33 AM, Peter F. Patel-Schneider wrote:

> I think that it would be best if RDF and OWL used the same list of acceptable datatypes.

I strongly disagree, for a variety of reasons. 

1. It is to be expected that RDF will permit constructions (not just datatypes, but including these) which may not be usable by OWL or RIF, since these more expressive languages support more complex entailments which may produce problems which do not arise in the more limited RDF framework. 

2. This idea. that OWL and higher levels of the 'layer cake', can impose their own special restrictions on the RDF used in that dialect, but that RDF itself is designed to be as general-purpose as possible, has been an accepted part of the overall semantic web design since the beginning of the whole enterprise. OWL-DL imposes a host of restrictions on RDF usage which are completely irrelevant to RDF users who do not use OWL, for example.  I see no reason to revise this design principle now. 

3. Many, perhaps most, uses of RDF do not use OWL, and OWL restrictions have no relevance to these users. To impose OWL-motivated retrictions on all RDF users would be bad engineering and I believe would violate the RDF WG charter. 

4. If we accept the general point, that 'higher' layers should impose conformity requirements on the base layer, then it applies not just to OWL, but also to all other WGs considering standards which potentially use RDF or which might impact RDF, including RIF, SPARQL, RDB2RDF, GLDWG and LDP, and possibly others. There is nothing special to OWL that should give it more influence over RDF design than other user communities. 

Note, this is not an argument against WG cooperation and interaction. My point is that *adding* datatypes to RDF simply *does not impact* OWL, other than perhaps suggesting an editorial comment stating that these datatypes are not to be used by OWL, if the OWL WG finds them unacceptable. So suppose we ask the OWL WG for comments, and they say that they do not wish OWL users to use these datatypes. Such a negative decision should not impact the RDF design in any way.


> (By the way, the OWL WG has been dormant waiting for XSD 1.1 to finalize, so there is a bit of work for that WG to do as well.)
> pete
> On 05/01/2012 08:57 AM, Richard Cyganiak wrote:
>> Dear all,
>> XSD 1.1 has added a number of new datatypes, and revised some of the existing ones. XSD 1.1 is now a W3C Recommendation. ISSUE-66 asks the question whether to add the new types to the list of XSD types allowed in RDF.
>> Alex has previously analysed the changes in XSD 1.1 from an RDF point of view:
>> http://lists.w3.org/Archives/Public/public-rdf-wg/2012Feb/0039.html
>> I fully concur with his findings and recommendations, and hence propose:
>> PROPOSAL: Resolve ISSUE-66 by adding xsd:duration, xsd:dayTimeDuration, xsd:yearMonthDuration and xsd:dateTimeStamp to the table of allowed XSD types in RDF Concepts ED Section 5.1
>> (RDF Semantics has a redundant list of the same types; this also needs to be changed accordingly, or removed in favour of normatively referencing RDF Concepts.)
>> Best,
>> Richard

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Received on Wednesday, 2 May 2012 18:14:59 UTC

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