Re: The 'resource' identified by a namespace name URI should be the namespace

-----Original Message-----
From: John Cowan <cowan@locke.ccil.org>
To: michaelm@netsol.com <michaelm@netsol.com>
Cc: xml-uri@w3.org <xml-uri@w3.org>
Date: Thursday, June 01, 2000 8:55 PM
Subject: Re: The 'resource' identified by a namespace name URI should be the
namespace


>Michael Mealling scripsit:
[..]
>> In order to compare two Resources (the logical thing) you can ONLY
>> compare their identifiers and thus, since all you have to compare
>> is the identifier, if one does not equal the other then the logical
>> things they identify are different.
>
>Not necessarily.  If the URIs are equal, the resources are the
>same; but if the URIs are not equal, the resources may or may not]
>be the same.  In the case of the "data:" URI scheme, distinct URIs
>implies distinct resources, but that isn't true in general.


Michael is right here, I think.  Because the only definitoin of a resource
is its URI,  resource equality is defined by the URI quality as
string equality of the URI.  That is a relation given us by the URI spec.

You can of course define other sorts of equivalences. If you do,
then consider which apply between the resources
http://www.w3.org/Icons/WWW/w3c_home
http://www.w3.org/Icons/WWW/w3c_home.png
http://www.w3.org/Icons/WWW/w3c_home.gif
(The first is generic, the second and third are content-type-specific)

When you define some wider form of equivalence than resource equality
then you always have that resource equality implies your-equivalence.
But not necessarily the reverse.

>> Right. What our problem seems to be is a terminology conflict.
>> In my terminology universe the namespace is the resource but it
>> is a logical thing that is only known or handled by its URI
>
>Well and good, but what is the URI of a namespace?  The Namespace Rec
>doesn't say.  It says that the *name* of a namespace is (i.e.
>has the form of) a URI *reference*.  Not the same thing at all.


Suggest that the URI of something given by a URI-reference is anything
other than the URI defined in eth URI spec as that referredto by the URI
reference
would be spilitting hairs to a fine degree indeed.

>The name of a resource is just one of its properties, not necessarily
>or typically the same as the URI at all.
>
>The book I was reading tonight has the URI of "urn:isbn:0671578081",
>but its *name* is the string "Komarr".  (Yes, I'm a Miles Vorkosigan fan.)


Let's say it has an identifier and a title.

>My proposal says how to discover the URI of a namespace; prepend
>its name with the string "data:,".  This works whether the namespace
>*name* has the form of an absolute URI, an absolute URI with a
>fragment-id, a relative URI reference, or whatever.



John, normally you are the voice of reason but here wit this data:
idea I fear you really have gone off at a tangent!  :-)  The data: URI
scheme
has a significance, that a data:,foo URI identifies that resource whose
*representation* (not name) is the string "foo".


If and when "foo" in some language is a representation of a namespace
then that would be a namesapce identifier.

I suppose (correct the details but get the gist)

    data:application/xml-schema,<schema></schema>

given the appropriate escaping of the <> could be used as a definition
of an empty namespace.  But in general the data: scheme is *not* meant as
a quotation system or encoding system to bury one URI within another.

If I had a key to turn all the messages on the list which mentioedn "data:"
a very pale shade of gr[e|a]y I would use it.....

Tim

>--
>John Cowan                                   cowan@ccil.org
> Yes, I know the message date is bogus.  I can't help it.
> --me, on far too many occasions
>

Received on Friday, 2 June 2000 23:12:30 UTC