[rdfweb-dev] advocating use of rdf:ID /rdf:aboutattributesonfoaf:Person tags

Libby Miller Libby.Miller at bristol.ac.uk
Mon Aug 18 15:31:43 UTC 2003

I think the key issue is that a thing can't have two urls in RDF, but a
foaf:Person could have two foaf:mboxes; so if someone uses the 'wrong'
uri for you (and many people use many uris for the same person in their foaf
files) - then RDF will see the different yous as distinct objects. Only
smushing could make them the same.

However, if your email address changes and you want people to use the
new one, the migration path is simple: you put both in your foaf file,
and smushers should then combine all the subjects of both addresses.
What you *can't* say in FOAF is that both these uris refer to you; also you
can't say, please smush these things together, because only
owl:inverseFunctionalProperties can do that as it stands, and the uri
for an RDF resource isn't a property of that resource in that sense.

So the mbox/mbox_sha1sum is a better migration path for people
identifiers that may change, and is more flexible.



On Mon, 18 Aug 2003, Bill Kearney wrote:

> > There's considerable value in having an email address, most people use
> > there's daily, there's no value to me in having a URI
> There's no current value?  I'd argue against this as quite a few folks are quite
> merrily contributing their part in the form of weblogs.  An entity they're quite
> a bit *more likely* to have greater dominion over than an e-mail address.  As in
> joe at workerbee.corporate.example.com is very fragile if the company fires him.
> Where as Joe owning his own domain, or paying for a hosted one, stands to be a
> lot less fragile.  Certainly not permanent for all time but let's get real,
> they're all faught with hassles (most of them quite similar).
> > , in any case, remember
> > the mbox is defined as the 1st user of that email address so even if it
> > stops being usable, it's still fine as an identifier.  We could say the same
> > with URI, however with URI's the controller of the domain is surely the
> > person who defines what the URI means, so we would not be able to do it.
> If the *person* owns the domain it's a lot MORE durable than an e-mail address
> might be.  Remembering, of course, that owning a website URL doesn't always me
> one has e-mail services on it.
> If not, then the same arguments made about URI control or fragility are directly
> applicable to e-mail as well.
> > Consider  the URI  http://Jim.example/foaf.rdf#me as soon as the owner of
> > jim.example changes who it points to (maybe they lost the domain) then all
> > FOAF which points to that URI is pointing at a different person, however if
> > they'd not used the URI, but had just used
> > foaf:mbox="mailto:jim at jim.example" then the Person hasn't changed, and the
> > new owner is specifically excluded from using that email address as a
> > foaf:mbox.
> Specifically excluded by whom?  Who's "in charge" of that idea?  It's just as
> fragile as a URI and possibly worse.  A URI, if retrieved, has the hope of
> containing /something/ that might help resolve the process.  An e-mail address
> is likely to just be a black hole; a message sent to it might elicit no reply at
> all.
> I'm not arguing that one is better than the other.  I'm suggesting that
> arguments against URI durability are weak, at best.
> -Bill Kearney
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