- From: Mike Dean <mdean@bbn.com>
- Date: Wed, 24 Apr 2002 20:20:03 -0400
- 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 Wednesday, 24 April 2002 20:26:41 UTC