- From: pat hayes <phayes@ai.uwf.edu>
- Date: Wed, 13 Nov 2002 13:00:36 -0500
- To: Jim Hendler <hendler@cs.umd.edu>
- Cc: www-webont-wg@w3.org
>Here's another one for you guys - really happened - I have two >students who wanted their ontologies linked - no changes involved >but: > A publishes P importing Q > B publishes Q importing P >If the WG decides to go with one of these import closures things >(and Pat's examples below show yet more reasons I worry if we've got >it right) we need to make sure we handle cycles in some correct way. Cycles should be OK as far as the MT is concerned. Actually following links requires care, obviously. Pat > -JH > > > > > >At 9:46 AM -0500 11/13/02, pat hayes wrote: >>Jeff, your email got me thinking about the intricacies which arise >>when thinking about imports in the context of a changing world. >>Here are few more example scenarios. In each case A, B, C etc are >>people, P, Q, R, etc are chunks of OWL in documents. 'changes' >>means altering the RDF at a given URL. >> >>1. >>A publishes P >>B publishes Q importing P >>A changes P (to P') >>C reads Q and imports P' >> >>Now, has C got it right, or not? Or should C have imported P (how?) >>Or should B have tracked A's changes (how?) >> >>2. >>A publishes P >>B publishes Q >>C publishes R importing Q >>B changes Q to Q' importing P >>D reads R >> >>Has D got it right? This is really a special case of the first one, >>but since the change involves an imports, the effect is magnified, >>as it were. Obviously, the change could be arbitrarily far along an >>imports-reference chain. >> >>3. >>A publishes P >>B publishes Q importing P >>A's server crashes >>C reads Q , concludes that the imports P is empty, archives the result >>A's server comes back online >> >>Now has C got it right? Or should C have refused to archive an >>empty-due-to-404 imports statement? >> >>Pat >> >>-- >>--------------------------------------------------------------------- >>IHMC (850)434 8903 home >>40 South Alcaniz St. (850)202 4416 office >>Pensacola (850)202 4440 fax >>FL 32501 (850)291 0667 cell >>phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes >>s.pam@ai.uwf.edu for spam > > >-- >Professor James Hendler hendler@cs.umd.edu >Director, Semantic Web and Agent Technologies 301-405-2696 >Maryland Information and Network Dynamics Lab. 301-405-6707 (Fax) >Univ of Maryland, College Park, MD 20742 240-731-3822 (Cell) >http://www.cs.umd.edu/users/hendler -- --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32501 (850)291 0667 cell phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes s.pam@ai.uwf.edu for spam
Received on Wednesday, 13 November 2002 13:00:05 UTC