Re: When are RDF statements asserted?

I'm going to note that in the parallel universe of "vernacular" XML
development, this seems to be similar to the debate about versioning and
namespaces. To summarize, the namespace by itself does not define the
application semantics of an XML vocabulary, and XML specifications
certainly don't for most of the non-W3C approved XML documents. So it
requires "out-of-band" information sometimes to determine what someone
*means* by the use of an XML element/attribute and their provenance
information. One can (but does not have to) retrieve a namespace
document to get authoritative information about an XML vocabulary as
given by the namespace URI it uses.

One could do something similar with applications of RDF/OWL, and put
default versioning and provenance information in the namespace document
(which could contain links to a FOAF file, RDF(S), and so on) of the
namespace URI used by a particular vocabulary. Most of these namespaces
seem just to have RDF schemas in there, but you could be put more there,
like provenance.

It seems straightforward, and there's even a RDF mapping for RDDL by
DanC, but I'm not sure about what RDF provenance vocabularies are out


Ora Lassila wrote:
> On 2006-03-28 13:24, "Richard Cyganiak" <> wrote:
>> On 28 Mar 2006, at 19:31, Ora Lassila wrote:
>> ...
>>>> Is it correct that out-of-band information (e.g. a web page stating
>>>> "All these files are up-to-date", or some nonstandard extension of
>>>> RDF) is necessary before an agent can safely act upon any RDF
>>>> statement?
>> ...
>>> IMHO, this is a question that could be asked about *any* document
>>> that has
>>> been published, not just RDF documents. The question is more about
>>> *who* is
>>> asserting. I could assert that, say, the Moon is made of cheese.
>>> Whether
>>> someone else chooses to *believe* this is another matter. Whether I
>>> assert
>>> that in RDF or in natural language is not so relevant.
>> Right. When you assert this in natural language, I can use out-of-
>> band information ("common sense") to decide wether to trust your
>> statement or not.
> Well, I guess common sense is only *one* of many ways how to make those
> decisions (e.g., I am not sure that common sense would have been enough to
> evaluate DanBri's example about the weapons of mass destruction).
>>> The key responsibility (again, IMHO) of "Semantic Web agents" is to
>>> make
>>> decisions (and inferences) about what information to trust, to use, to
>>> discard, to keep but not trust, etc.
>> That makes a lot of sense. Am I correct when I say that RDF and OWL,
>> at the current state of standardization and common practice, don't
>> provide a solution for this trust problem, and application developers
>> are on their own?
> Yes. I don't think RDF and OWL should, per se, even provide a solution,
> given that the required mechanisms can be application-specific. Could one
> potentially *model* some of those mechanisms using RDF and/or OWL? Why not.
>     - Ora


Harry Halpin,  University of Edinburgh 6B522426

Received on Tuesday, 28 March 2006 22:19:49 UTC