- From: pat hayes <phayes@ai.uwf.edu>
- Date: Sat, 28 Sep 2002 23:04:42 -0500
- To: seth@robustai.net
- Cc: www-rdf-comments@w3.org
>pat hayes wrote: > >>>On Saturday 28 September 2002 04:46, Brian McBride wrote: >>> >>>> At 20:26 09/09/2002 -0700, Graham Wideman wrote: >>>> >>>> [...] >>>> >>>> >Is there, for example, some convention whereby a block of RDF can say >>>> >"This block of RDF abides by the RDFS schema to be found here", in the >>>> >same fashion that an ordinary XML file can specify a DTD by which it >>>> > abides? >>>> >>>> Graham, >>>> >>>> Have a look at isDefinedBy and seeAlso and see if they meet your needs. >>> >>> >>>AFAIK the above properties are mostly for human consumption, although the >>>first one implies some authority. >>> >>>It would be grate if we had a property with consistent meaning, as in "this >>>resource completes the graph, providing metadata about the subject". >> >> >>The trouble with this is that there is no such thing as >>'completing' a graph. The aim of RDF is to provide a notation in >>which information from many sources can be combined together, so >>the 'closed-world' kind of picture where graphs have boundaries >>defined by other graphs really does not fit very well. > >Are you saying that document-A does not provide a boundary to the >RDF graph which is endoced by document-A? So do all RDF triples in >whatever document written by whomever just form one big graph In one sense but not another. There are clearly syntactic and operational boundaries between graphs. But publishing a graph amounts to asserting it, and you can draw conclusions from any assertions you can find. I know all sorts of things that I read somewhere or was told, and Ive forgotten where they came from; but I still know them and still use them in my thinking. I think it is fair to say that all the published RDF in the world can be thought of as one huge graph, in this sense. (Bnodes complicate this simple picture a bit, but the essential point is the same.) >and we (and RDF MT compliant agents) are to ignore the document boundaries? Certainly. In fact, they are completely invisible to the RDF semantics. I envision RDF processors which scour the web looking for content relevant to their goals, plucking it out of other graphs and merging it together freely and drawing consequences from it. If such an engine simply forgot about the original graph boundaries that would not affect the conclusions it came to. >Hmm .... then there would be no boundary between the triples you >will find by dereferencing <http://robustai.net/sailor/paradox.rdf> ><http://localhost:2187/node.html?at=%3Chttp://robustai.net/sailor/paradox.rdf%3E> >and the triples you find from dereferencing ><http://www.w3.org/1999/02/22-rdf-syntax-ns#Property> Well, 'dereferencing' here just means accessing according to the URL/HTTP protocols, and of course at that level the graphs are separate documents. But in terms of their meaning, each graph asserts the triples in it, in the very same way that it would if those triples were somewhere else. The only things that matter to the *content* are the triples that get asserted. Pat > .... wow, I dont know how to make work, .... I must be missing something. >Seth Russell >http://radio.weblogs.com/0113759/ -- --------------------------------------------------------------------- IHMC (850)434 8903 home 40 South Alcaniz St. (850)202 4416 office Pensacola (850)202 4440 fax FL 32501 (850)291 0667 cell phayes@ai.uwf.edu http://www.coginst.uwf.edu/~phayes
Received on Sunday, 29 September 2002 00:04:24 UTC