W3C home > Mailing lists > Public > semantic-web@w3.org > June 2007

Re: homonym URIs (Re: What if an URI also is a URL)

From: Jon Hanna <jon@hackcraft.net>
Date: Wed, 13 Jun 2007 14:41:33 +0100
Message-ID: <466FF40D.8010703@hackcraft.net>
To: Pierre-Antoine Champin <swlists-040405@champin.net>
CC: Richard Cyganiak <richard@cyganiak.de>, Pat Hayes <phayes@ihmc.us>, Sandro Hawke <sandro@w3.org>, semantic-web@w3.org

Pierre-Antoine Champin wrote:
> I think (as Pat, if I read him correctly) that punning/overloading can
> not be avoided. I would add that it can be deliberate, for practical
> reasons (e.g. e-mail adress / person, predicate / function), but it can
> also be *unintentional*. Let me explain :

I think this sort of punning is a red-herring, because it isn't really a 
pun.

If I put an email address into a context where the expected input is 
"email address of person in question" then there is no pun; it 
identifies a mailbox. That the mailbox is in turn being used to identify 
a person doesn't make it a pun.

> we keep using the same word for slightly different things (e.g. a city
> as an administrative entity or as a populated location), as long as the
> difference between them is not relevant to us. The same will be true of
> URIs that we will create and put in RDF. We can not expect everybody on
> the web to require the same level of detail on every part of the world
> about which they make RDF statements.

If you have a URI that means "London; the administrative entity" then it 
means just that.

If you have a URI that means "London; the populated location" then it 
means just that.

If you have a URI that means "London; a populated location which was 
made an administrative entity" then it means just that.

You can go from one to the other if you know the relationship between 
them. If I start thinking of London - populated location and the context 
makes it apparant I should be thinking about the administrative entity 
then the mental switching of gears is doing exactly that.

There are clearly problems if a system doesn't know about that 
connection between the three different concepts above, but if it's meant 
to know about them then the problem isn't in the URIs.

> An intuition is that owl:sameAs may be too strong a statement
> in a context where URI can be ambiguous.

I think that's definitely true.
Received on Wednesday, 13 June 2007 13:42:17 UTC

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