- From: Tim Berners-Lee <timbl@w3.org>
- Date: Thu, 2 Mar 2000 13:02:31 -0500
- To: "Pierre-Antoine CHAMPIN" <champin@bat710.univ-lyon1.fr>, "ML RDF-interest" <www-rdf-interest@w3c.org>
-----Original Message----- From: Pierre-Antoine CHAMPIN <champin@bat710.univ-lyon1.fr> To: Tim Berners-Lee <timbl@w3.org>; ML RDF-interest <www-rdf-interest@w3c.org> Date: Thursday, March 02, 2000 4:17 AM Subject: Re: Subclass of Thing/Resource >I'm not sure we have to make explicit the different levels of interpretation of resources. >Anyway, the real entity "behind" the resource is often out of range for the system ! Nothing is "out of range" to our discussion or to RDF. >And I think there is no such thing as easy as dereference for URI - >there can be an arbitrary number of interpretation levels. I disagree. The number of interpretation levels cannot be arbitrary or hopeless confusion will result. Documents describe documents which describe documents, and you must be able to reefr to a specific one in the chain. >e.g. > ><rdf:Description about="http://www.somewhere.org/index.html"> > <play:protocol> HTTP 1.1 </play:proptocol> > <play:size> 3 Kb </play:size> > <play:mime> text/html </play:mime> > <play:creator> Pierre-Antoine </play:author> ></rdf:Description> > >none of the properties above applies to the same interpretaion of the URI The properties themselves can be defined to make sense here. You may not want to do it like that, but if really that is what you want to write, you can define the properties as play:protocol ......... the protocol used in a succesful derefernce of a resource's URI. play:size .................the number of bytes in the body of at least one representation of the resource; play:creator: the common name of the creator of the resource. That works. You can define things like "the only size of any representation of the resource" of course - one would have to look at the play spec. >should we instead write ? > ><rdf:Description about="http://www.somewhere.org/index.html"> > <play:protocol> HTTP 1.1 </play:protocol> > <play:content> > <rdf:Description about="file://server.somewhere.org/var/httpd/index.html"> Here you seem to be interoducing more information - stuff about another resource, and reating it to the original. > <play:size> 3 Kb </play:size> > <play:content> > <rdf:Description about="mime:xxx"> > <play:type> text/html </play:type> > <play:content> > <rdf:Description about="abstract-document:yyy> > <play:creator> Pierre-Antoine </play:creator> > </rdf:Description> > </play:content> > </rdf:Description> > </play:content> > </rdf:Description> > </play:content> ></rdf:Description> > >I don't think so. You don't have to define all that mess, no. You can just define the "play:size" as the length of the resource. That means the length of the thing returned when the HTTP protocol is used to dereference it. You don't have to say that explicitly in RDF. (You might one day in the schema for play: inth edefinition of play:size) >Sure a web page or an e-mail address IS NOT the corresponding person. >Neither is its employee ID... No. Either can be used to identify a person. http://www.w3.org/DesignIssues/Identity.html#Expressing >Though, could we prevent people using the dublin core properties this way : > ><rdf:Description about="http://www.somewhere.org/somedoc"> > <dc:Creator rdf:resource="mailto:John@somewhere.org"/> > <dc:Creator rdf:resource="http://www.somewhere.org/~Paul/"/> > <dc:Creator rdf:resource="employee://somewhere.org/12345"/> ></rdf:Description> > >I don't think so ! Yes we can, I hope! IMHO the above is a mess. Is this what dc expect to happen? 0. We could define (if starting from zero) define dc:creator to have range dc:person where a person is the domain of properties dc:mailbox and sc:homepage and dc:commonname. That is the best solution. 1. We can write a schema which specifies the range of Creator as being a string and says it is a common name. 2. We could define dc:creator-name and dc:creator-mailbox and dc:craetor-homepage seperately with the semantci s being the same as 0 by definition. 3. We can if people really want to do things like that we can define dc:creator-whatever as the union of craetor-mailbox and creator-homepage which is yukky and forces oene to find the type of the object before it can be used. And that doesn't help until we have mutually disjoint types. >URIs are ambiguous, yes, they have more than one interpretation level, yes. No, no. We should be clean or no reasoning from all this will be possible. IMHO. >We can't prevent people from using URI with different interpretations, >so we'll have to use the context to tackle with it. > > this is not a bug, this is a feature -- IMHO we agree to differ then. tim > Pierre-Antoine > > >--- Quid quid Latine dictum sit, altum viditur > Whatever is said in Latin sounds important. sed quid quid in RDF dictum sit, altum est.
Received on Thursday, 2 March 2000 13:02:39 UTC