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[LC Response] To Zhe Wu Re: OWL 2 LC Comments

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Wed, 04 Mar 2009 16:38:17 -0500 (EST)
Message-Id: <20090304.163817.133238338.pfps@research.bell-labs.com>
To: alan.wu@oracle.com
Cc: alanzwu@yahoo.com, public-owl-wg@w3.org
Dear Zhe,

Thank you for your message
<http://lists.w3.org/Archives/Public/public-owl-wg/2009Jan/0083.html>
on the OWL 2 Web Ontology Language last call drafts.
 
Your message contains multiple sections, affecting more than one
document, and will thus generate multiple replies.  This response
is for sections 4 and 8 about the datatypes in OWL 2 RL.

We have adjusted the datatypes of OWL 2 RL to include those XML Schema
datatypes that are derived from xsd:string and xsd:integer, including
xsd:positiveInteger, plus xsd:boolean.  These were excluded from OWL 2
RL because of a mistaken analogy with OWL 2 EL and OWL 2 QL, namely that
intersection of value spaces must be either empty or infinite to
maintain the desired properties of the profile.  It turns out that this
is not needed in OWL 2 RL to obtain its desired computational
properties.  As any OWL 2 RL tool has to process xsd: string and
xsd:integer, the added implementation burden to support these datatypes
is negligible.

The situation with owl:rational and owl:real is different.  The working
group has received complaints that implementing these datatypes may
require significant effort on top of a rule reasoner.  Therefore
owl:rational and owl:real have been removed from OWL 2 RL.  This
possibility was mentioned in Feature At Risk #2.

The diffs for these changes can be found at
<http://www.w3.org/2007/OWL/wiki/index.php?title=Profiles&diff=18687&oldid=18109>

The working group notes that Oracle has also brought up concerns with
the treatment of xsd:float and xsd:double.  These two datatypes are not
currently part of OWL 2 RL.   If this situation changes the working
group will communicate with you.

Please acknowledge receipt of this email to
<mailto:public-owl-wg@w3.org> (replying to this email should
suffice). In your acknowledgment please let us know whether or not you
are satisfied with the working group's response to your comment. 

Regards,
Peter F. Patel-Schneider
on behalf of the W3C OWL Working Group 
Received on Wednesday, 4 March 2009 21:38:04 GMT

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