- From: William Waites <ww@styx.org>
- Date: Mon, 13 Jun 2011 22:51:39 +0200
- To: Pat Hayes <phayes@ihmc.us>
- Cc: Danny Ayers <danny.ayers@gmail.com>, Richard Cyganiak <richard@cyganiak.de>, Alan Ruttenberg <alanruttenberg@gmail.com>, Linked Data community <public-lod@w3.org>, Michael Hausenblas <michael.hausenblas@deri.org>
* [2011-06-12 22:52:18 -0700] Pat Hayes <phayes@ihmc.us> écrit: ] OK, I am now completely and utterly lost. I have no idea what you ] are saying or how any of it is relevant to the http-range-14 issue. ] Want to try running it past me again? Bear in mind that I do not ] accept your claim that a description of something is in any useful ] sense isomorphic to the thing it describes. As in, some RDF describing, ] say, the Eiffel tower is not in any way isomorphic to the actual ] tower. (I also do not understand why you think this claim matters, ] by the way.) So in the previous email, Danny used the important word - relevant. Let's unpack that a little bit. Suppose we have no range-14 and all these RDF statements out there are all mixed up about what they refer to. Well, not completely mixed up. They're kind of clumped together, web pages and the things they are about tend to get confused but probably the chain of inferences that lead you to believe that the Eiffel tower is a dog is pretty unlikely. So there is some relationship between a description of the Eiffel tower and the tower itself. The relationship is akin to similarity in a very specific way - they are similar enough that someone thought it made sense to write down that the tower was 356m tall. Unfortunately they got confused and wrote down that the web page was 356m tall. No matter, they are still different enough in the relevant ways that anyone interested in heights on the order of hundreds of meters is unlikely to be confused. Same with the dog. Is the distinction between the dog and the picture important to me? Maybe, maybe not. It depends what I'm trying to do. If I want to make sure that I can recognise the doc when I meet her, a picture or the actual dog might do equally well. So that's the thing, similar or different in the relevant respects for the purpose at hand. The purpose at hand is necessary to figure out relevance. Just deriving all the possible things that can be entailed from the information you have is no good. You have to derive the relevant things in a particular context. You have to throw out givens that are irrelevant to you or that lead you to irrelevant or nonsensical entailments. In the general case this is hard. It's not even clear if it is relevance understood like this is computable. The intent of the user is so clearly in the loop providing a reference frame for evaluating relevance and capturing and representing a user's intent is not something we have a good way of doing apart from hand-crafting interactions. Is it doable in simple cases (with rules programmed by humans) like figuring out the foaf:knows graph where people and their homepages can just be merged without too many bad side-effects. We need a different kind of rule here - a cut rule. That says if some condition obtains, *remove* some statements. For example, remove all { ?doc a foaf:Document } before running the productive rules might be a common one where we know that we aren't interested in information resources. Cheers, -w -- William Waites <mailto:ww@styx.org> http://river.styx.org/ww/ <sip:ww@styx.org> F4B3 39BF E775 CF42 0BAB 3DF0 BE40 A6DF B06F FD45
Received on Monday, 13 June 2011 20:52:13 UTC