- From: Pat Hayes <phayes@ai.uwf.edu>
- Date: Wed, 12 Sep 2001 17:11:35 -0500
- To: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
- Cc: w3c-rdfcore-wg@w3.org
OK, let me start with a clean whiteboard here. The issue seems to be, that if URIs are 'names', ie refer to things, then what a given URI might refer to may change with time. And, moreover, that this isn't something to try to ban, but an intuitive and reasonable and useful thing. OK, lets accept that. Now, what do we do about it? Several strategies are possible. 1. Shelve it as an issue to be dealt with later, and ignore it for now. (Pat's favorite.) 2. Somehow incorporate it into the semantics of RDF. The immediate problem here is that RDF as it stands hasn't a shred of syntax which explicitly refers to times or changes or tenses or anything like that, so how do we reconcile the timeless nature of the language with the ever-labile nature of its referents? 2a. By saying that the *real* referent doesn't change, but is something like the entire history of all the values it can have as time goes by. (GK's idea, right?) 2b. By saying that the RDF MT refers to an 'instantaneous use' of RDF, ie to the meaning of RDF at some instant, and allow that this meaning might change when the same piece of RDF syntax is used a second time. Moving between these seems to be like your 'currying' point, where the time-index gets shifted from the assertion (triplet) in case 2b to the URI (which then gets time-sliced) in case 2a. 3. Say that RDF is 'really' a modal logic, it just hasn't got any modalities defined yet, and so the MT corresponds to a 'temporally possible world'. (This is one approach to how to do the 'later' in option 1, in fact). 4. Insist that RDF really is timeless and doesn't change, and so the URIs must be interpreted timelessly also, invoking some kind of integral dating scheme (Larry Masinter's idea). ----- I can see some merit an all these ideas, but I guess that I still think that it is best to shelve this right now. The issue isn't going to go away, but it seems to be outside the WG scope. Pat -- --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola, FL 32501 (850)202 4440 fax phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes
Received on Wednesday, 12 September 2001 18:11:39 UTC