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[LC Response] To Susie Stephens Re: OWL2 Feedback from Lilly

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 19 Feb 2009 11:22:35 -0500 (EST)
Message-Id: <20090219.112235.97717955.pfps@research.bell-labs.com>
Cc: public-owl-comments@w3.org
Dear Susie,

Thank you for your message
on the OWL 2 Web Ontology Language last call drafts.
part of which was supported by Frank van Harmelen in

1/ Concerning OWL 2 Profiles:

The OWL 2 effort was designed to extend the constructs of OWL to
encompass those that users had asked for, that researchers could
specify, and that implementers had or could implement.  It is thus
definitely the case that OWL 2 is supported by research.  However, the
driving force was much more users and implementers.

The OWL profiles had a similar genesis.  If the driving force behind the
OWL profiles had primarily been research, then there could have been many
more profiles, and the profiles would have had a different focus.

This is particularly the case for OWL RL.  OWL RL is designed to capture
the essence of several partial implementations of OWL functionality by
means of forward chaining rules.  Previously all that could be said
about these implementations was that they were partial implementations
of OWL.  OWL RL provides a much more complete characterization for
rule-based implementations of OWL.  Yes, there are formal results
underlying OWL RL, but these formal results are descriptive of the
extant implementations instead of being driving forces for the design of

OWL EL and OWL QL also do have a formal basis.  However they again are
attempts to capture existing implementation techniques and existing

The WG also expects that there will be tools that analyze OWL 2
ontologies and determine which profile they fit into, just as was the
case in the past.

In any case, the OWL 2 profiles are simply there for those who may be
interested taking exploiting desirable characteristics of
implementations of the profiles.  If one does not care about these,
there is no need to consider the profiles at all.  The Primer document
discusses the different profiles, and provides some guidance as to which
profile to use.

2/ Concerning the Structural Specification and Functional-Style Syntax:

Thank you for your kind words on the introduction and other parts of
this document.  Also thank you for bringing to our attention the
extraneous word in Section 2.3.

There is no notion of ownership of entities in OWL, so "ownership" is
not transferred with imports.  It is the case, however, that entities in
imported ontologies can be used in the importing ontology just as if the
contents of the imported ontology were part of the importing ontology.

The situation with -0 and +0 is unique, and is dictated by the treatment
of floats in XML Schema datatypes.  There are no other similar
situations.  The literals for booleans are similarly dictated by XML
Schema datatypes.  If "yes" and "no" are added to the XML Schema
datatype boolean, they will then be available in OWL.

3/ Mapping to RDF Graphs:

It is definitely the case that mapping from the Functional Syntax to an
RDF graph and back again does not affect the meaning of an OWL 2
ontology.  The OWL WG expended considerable effort to make this mapping
as general as possible and to specify it in more detail than previously.

The OWL WG does not intend to make any changes in response to your
message, except that the Primer is still not in Last Call and its
discussion on profiles may be improved in response to your concerns.

Please acknowledge receipt of this email to
<mailto:public-owl-comments@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 Thursday, 19 February 2009 16:22:44 UTC

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