[Fwd: Re: LANG: compliance levels]

-------- Original Message --------
Subject: Re: LANG: compliance levels
Date: Wed, 24 Apr 2002 20:20:03 -0400
From: Mike Dean <mdean@bbn.com>
To: Frank van Harmelen <Frank.van.Harmelen@cs.vu.nl>
CC: Enrico Motta <E.Motta@open.ac.uk>, Ziv Hellman <ziv@unicorn.com>,Ian Horrocks <horrocks@cs.man.ac.uk>, herman.ter.horst@philips.com,Peter Patel-Schneider <pfps@research.bell-labs.com>,Christopher Welty <welty@us.ibm.com>, Jim Hendler <hendler@cs.umd.edu>,Raphel Volz <rvo@aifb.uni-karlsruhe.de>,Deborah McGuinness <dlm@ksl.stanford.edu>, www-archive@w3.org,phayes@ai.uwf.edu


I'm uncomfortable that "Level 1 RDF Schema on Steroids"
focuses on global domain/range restrictions rather than
local restrictions.  I've found general consensus that local
restrictions are preferable.

I think we want as seamless a progression as
reasonable/possible from Level 1 to Level 2 (so users can
graduate as they appreciate and/or need additional
features).  If we only support global restrictions in Level
1, I'm tempted to suggest that we drop local restrictions
from Level 2.

I think cardinality (preferably arbitrary, but at least
0+/0-1/1/1+/n) needs to be addressed in Level 1.  Most current
DAML+OIL ontologies include cardinality restrictions.  XML
Schemas typically include cardinality restrictions.

I'm torn on the functional property issue.  While I think a
global restriction could be a useful hint to reasoners, I
think this would often be misused.  For instance, a
usSocialSecurityNumber property uniquely identifies a Person
but not a BankAccount.  As suggested by others in the past,
I'd prefer a local property like

  :usSocialSecurityNumber owl:uniquelyIdentifies :Person

Generalizing and going out on limb a bit, I'm concerned that
we're giving RDF too much sway (ignoring charter issues).
If WebOnt is successful, I expect most folks will use it
rather than RDF.  This is typical in layered systems
(compare the amount of application code written to use
10baseT, Ethernet datagrams, IP, TCP/UDP, and HTTP which are
(roughly) successive layers in the ISO OSI Reference Model).
I'm a bit concerned that we're making decisions that will
inconvenience millions of future WebOnt users for the sake
of hundreds of current RDF users.

	Mike

Received on Thursday, 25 April 2002 07:18:57 UTC