- From: Pat Hayes <phayes@ai.uwf.edu>
- Date: Wed, 3 Apr 2002 13:40:07 -0600
- To: Dan Brickley <danbri@w3.org>
- Cc: w3c-rdfcore-wg@w3.org
>On Mon, 25 Mar 2002, Graham Klyne wrote: > >> At 12:29 PM 3/25/02 +0000, Jan Grant wrote: >> >This is, surprise, going down a rathole fast, so this is my last pulic >> >post on the topic... > >don't say I didn't warn you :-/ > >I don't want to slow down RDF Core process, but do want to get to the >bottom of this. Maybe www-rdf-interest or -logic unless we suddenly all >agree on something? > >Any further discussion here should probably be couched in terms of >proposed changes to our Working Draft text, and associated with an open >issue. The closest I can find in the Issue Tracking document is >http://www.w3.org/2000/03/rdf-tracking/#rdfms-assertion > >See below for a draft addition to the MT spec. > >> >A better bet (I think) is to just do something Herbrandish - that is, >> >keep the current definition of "interpretation"; if you _do_ wind up >> >with one of Dan's problematical graphs (that is, one with a URI-labelled >> >node with no "meaning", ie, which doesn't denote anything*), you don't >> >really hurt yourself by letting it denote some mathematical figment that >> >doesn't collide with anything else. >> >> That sounds very like what I was trying to say. > >I think we have some notion of a "Web-sanctioned interpretation" >underlying our thought on this. There are certainly >interpretations (alice-in-wonderland ones, for eg.) where poison-URIs >denote. The concern is that there may be no Web-sanctioned ones, ie. >when we buy into the global meaning of the urirefs, we waive our >right to make up arbitrary mappings. The MT does acknowledge that >urirefs have global meaning imposed by our shared Web understanding >of these node labels. Does that W-si idea amount to something more than a vanilla interpretation of (possibly hypothetical) merge of all the information on the Web (about the concept in question, maybe) ? Or is it an entirely different kind of thing altogether? For example, consider a URL. As far as RDF is concerned it is simply an identifier, but the Web uses it as global file locator. Which of these is the 'global meaning' ? > >I would be happy with the Herbrandish workaround, so long as there >could be Web-sanctioned interpretations of a 'poisoned' graph. The >Web-sanctioned interpretations of a graph, as I introduce the phrase, >are those that are respectful of the public meaning of each uriref. >For those, we must defer to specs beyond RDF's (eg. URI2396, TAG work >etc.). > >There are perhaps 'hybrid' interpretations in which 'good' URIs denote >things in the world (fixed by Web/TAG conventions for meaning of urirefs Are there any such conventions for fixing the worldly referents of uris? I would be amazed to find any. I don't really see how there could be any, or how they could be stated if there were any. >), while >'poison' ones denote (some figment of our choice). I'm nor sure that >is a very clear partition, since it is those same Web/TAG/2396 conventions >that determine whether a uriref has public meaning. It might be good enough. >Below is an attempt at characterising such a 'hybrid' interpretation >(without imposing it). I don't think the MT can go any further than that. > >We should be wary of trying to make the MT do work that MTs aren't >designed for. But we should also be wary of leaving a gap in our account >of the meaning of RDF/XML documents. > >Does the following work for anyone? Not for me. I'd rather not get into this territory at all, except maybe to put up warning flags. > >[[ >Note: urirefs, as referring expressions, have their meaning fixed through >a number of social, legal and technical mechanisms. The RDF MT does not >itself impose any particular interpretation on an RDF graph. An >interpretation for an RDF graph in which the denotation of uriref labels >is fixed by the public meaning of urirefs is termed a <em>Web-sanctioned >interpretation</em>. It is beyond the scope of the MT to provide a >detailed discussion of Web-sanctioned interpretations. Damn right :-) >At this time, it is >not clear whether the Web's use of uriref identifier syntax allows us to >assume that all urirefs denote. We do not know whether the Web >architecture guarantees that every RDF graph has a <em>Web-sanctioned >satisfying interpretation</em>. Well, any RDF graph, no matter how large (it can even be infinite), does have a satisfying interpretation, so... > An interpretation for an RDF graph in >which the denotation of uriref labels is fixed by the public meaning of >urirefs, augmented by the assumption that each uriref denotes, is termed >an <em>augmented Web-sanctioned interpretation</em>. This notion >allows us to discuss the ascription of propositional content to RDF graphs >that contain nodes and edges labeled with urirefs, without concern for >whether a public ("Web") meaning is assigned for each uriref. >Without making this >additional assumption, there may be RDF graphs whose (publically >meaningless) uriref labels ensure that there are no satisfying ><em>Web-sanctioned</em> interpretions for the graph, because nodes are >labeled with non-referring urirefs. This notion is particularly relevant >to Web applications that exchange RDF graphs employing the RDF Core >reification vocabulary (ie. Statement/predicate/subject/object) >since nodes will often be labelled with uriref data from untrusted >sources. >]] > >Or we could leave this for version 2... I was just trying to draft a >'health warning' flag to stick outside the rathole... (and something we >could point the TAG or URI CG at). > >Dan -- --------------------------------------------------------------------- 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, 3 April 2002 14:40:08 UTC