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

On Thu, Jun 01, 2000 at 09:20:57PM -0400, John Cowan wrote:
> 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.

Actually no. I guess using your parlance, the Resource and the URI
are the same thing. A Resource (the logical thing) is bound so tightly 
to its URI that it is only known by it and if known by some other
URI then it is a different Resource. 

> > 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.
> The name of a resource is just one of its properties, not necessarily
> or typically the same as the URI at all.

I'm not sure I followed that all that well but..  The URI is its name. 
The namespace is a logical object that has names (which in this case 
takes the form of a URI). 

> 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.)

Your mixing the defintions of 'name' here. "Komarr" is not its name. Its
its title. A book doesn't have one single name. It is known by its
various names depending on the criteria by which someone applies names.
The ISBN authority will call ISBN a name and the title just some
meaningless piece of metadata. But still, if I say I have some logical
thing I call a book and it has the name urn:isbn:12341234 and you say you 
some other logical thing called a book and its name is guid:213423423
then we don't know wether or not we have the same book. And if that's
all the information we're allowed to have then we can never know
if we have the same book. Inversely, since that's all we have, we
know that the mapping between the name and the thing it names is
injective since to have a different name implies a different logical thing
which it names.

> 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.

I still don't get the distinction. Why do you need "the URI of a namespace"
if the namespace is already named by a URI (assuming we semi-deprecate
relative URIs)? 

-MM

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Received on Thursday, 1 June 2000 22:12:51 UTC