Subject: Re: URIs vs URLs? Resent-Date: Tue, 4 Jan 2000 15:01:21 -0500 (EST) Resent-From: www-rdf-interest@w3.org Date: Tue, 04 Jan 2000 21:01:07 +0100 From: Jonas Liljegren To: RDF Intrest Group CC: Pierre-Antoine CHAMPIN References: 1 , 2 , 3 Pierre-Antoine CHAMPIN wrote: > > 2) About rdfs:Class and other "virtual" resources. > Many resources are "defined" by ways of RDF. > Their URIs don't return their content (which often doesn't even exist) > but some description of the resource. > That's what Jonas raises : > > QUESTION 2 : how do I know when an URI points to the resource, or to a description of the resource > This question raises also when we're dealing with real-world-objet-URIs (like person's), > because those URIs will doubtfully return the resource itself ! As I understund. The best way to handle this is to give the resource a type. This could be a mime type or any other type of type. The rdfs:Class resource has the type rdfs:Class. The application will have to understand that this is an abstract type. The same goes for types like Person. The application will have to understand that this is a living entity and that those things can't be retrieved over the internet. Any content of the URL would by interpretation of this semantics, be regarded as a description of the entity. You would like to have a service that could tell you that a Person is a living entity, and that a living entity is a material thing. With a help like this, your application would only have to know that retrievable resources of material things will probably contain a description of the corresponding entity. -- / Jonas - http://paranormal.o.se/perl/proj/rdf/schema_editor/