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URx Questions

From: Sean B. Palmer <sean@mysterylights.com>
Date: Mon, 21 Jan 2002 03:37:23 -0000
Message-ID: <000e01c1a22c$f1aea5a0$06560150@localhost>
To: "Patrick Stickler" <Patrick.Stickler@nokia.com>
Cc: <uri@w3.org>
Hi Patrick,

Sorry for taking so long to go through your recent URx publications;
here are some fairly innane questions, and some general comments.

My first Q is about the hierarchial URN scheme. Michael pointed out
that they can have domain names as authority components, which isn't
all that persistent. UUIDs would be alright, but they're fairly
difficult to generate. The other option is a tag-esque "domain,date"
component - which brings me to the question: how does "hrn:" differ
from "tag:"? I presume that the hierarchial aspect is what you're
after, although I'm not sure what the relationship between the
segments is. Why not use ":" as a hierarchial segment delimiter in
"tag:"? Note that "tag:" was going to be registered as a URI, and URN

Next Q: I can't work out what "voc:" is for, if anything. The draft
states: "This provides a more robust and safe treatment of unqualified
names than the 'online:' or 'genid:' treatments employed by most RDF
systems to date.", so it sounds as if they're meant to be replacements
for anonymous nodes... but the structure of the URIs suggests

I've also been wondering about the taxonomy in general. A lot of
people will tell you that an HTTP URI is just as good a persistent
identifier as any URN - it's the social contract that matters, and
HTTP URIS are widely deployed. The URN/URL/URP taxonomy feels rather
artificial to me, and I fear that creators of new schemes will have to
beg to you as the arbiter of where a new scheme belongs. [BTW, I'm not
sure I would have chosen the acronym "URP". Every time I write it, I
feel like excusing myself afterwards].

For example, you've listed ESL as a URV. I can see the motivation
behind that, and I would agree - if not for the fact that ESL could
easily have been submitted as a URN NID. At the moment, I am one of
those who feel that the boundary between URP and URN is not all that
solid. [In fact, I wonder why there isn't a "uri-x:" alternative of

I'm not sure what the utility of the "qname:" scheme is. In fact, many
of the drafts are lacking in describing the utility of the schemes
themselves. Whilst this seems to be common practise, it's something
that I battle against. All new schemes should have a detailed space
describing their purpose and motivation, because it obviates arguments
later on. If you could prepare a summary of the aims of each scheme,
that would be rather useful.

Kindest Regards,
Sean B. Palmer
@prefix : <http://purl.org/net/swn#> .
:Sean :homepage <http://purl.org/net/sbp/> .
Received on Monday, 21 January 2002 02:02:14 UTC

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