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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
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

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. 

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

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