W3C home > Mailing lists > Public > semantic-web@w3.org > May 2006

Re: How to assert equivalence of URIs ?

From: Danny Ayers <danny.ayers@gmail.com>
Date: Tue, 30 May 2006 20:08:51 +0200
Message-ID: <1f2ed5cd0605301108x61deff7dwe2fb23573bc281c@mail.gmail.com>
To: "Max Völkel" <voelkel@fzi.de>
Cc: semantic-web <semantic-web@w3.org>

On 5/30/06, Max Völkel <voelkel@fzi.de> wrote:
>
> Hi Andrea and all,
>
>   as  URIs  are  a cornerstone of RDF and then in turn of the ontology
>   languages layered on RDF, it would make sense to me, to have an
>      rdfe:sameAs
>   property in the yet-to-be-defined rdf-extensions namespace.
>   The  semantics  of  this  could  be  that  a tool processing data is
>   allowed to normalise all URIs to ONE of the given rdfe:sameAs URIs.
>   Maybe even state a preferred URI:
>     rdf:mainURI
>   to which we normalise.

I can see how this could be useful, but on the one hand what would it
offer that isn't already available in RDFS/OWL? ...on the other,
wouldn't it open a whole new can of worms for RDF semantics?

If I understand correctly, what is (apparently) lacking is something
that behaves something like HTTP 3xx codes maybe with wildcards like
Apache mod_rewrite, only without the HTTP.

I suppose owl:sameAs causes problems in its lack of uniformity (from
the URI point of view), in that saying two classes are the same has
very different implications than saying two individuals are the same.

 It's not hard to imagine a preprocessor taking care of the preferred
URI selection at the syntax level, but this doesn't make the
complexity issues with mixing individuals and classes/properties go
away. I'm pretty sure something could be hacked together right now
using regexs and/or rules, but for a general solution it does seem
like messing with the opacity of URIs. Maybe I've misunderstood the
problem, or am looking at it wrongly, but I don't see any easy
solution that would add to what we've got.

Whatever, I do think it would be useful if someone could clarify the
requirements here, what is lacking? There's an RFC which says whether
or not two URIs are (probably) the same, so I'm assuming this is about
determining whether the resources they identify are the same. Or does
it go further, into saying that specific representations of two
resources are the same? That's probably a Pandora's Box (of worms).

Cheers,
Danny.

-- 

http://dannyayers.com
Received on Tuesday, 30 May 2006 18:08:57 UTC

This archive was generated by hypermail 2.4.0 : Thursday, 24 March 2022 20:40:59 UTC