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RE: abstract identifier: definition seems to be missing something

From: Drummond Reed <drummond.reed@cordance.net>
Date: Sun, 21 Sep 2008 23:45:34 -0700
To: "'Dan Connolly'" <connolly@w3.org>, "'www-tag'" <www-tag@w3.org>
Message-ID: <9D641F6D7B1C4FE88409EC3620502C87@ELROND>

Dan, you are quite right -- the definitions were missing the implicit
assumption that they are all relative to a given resolution protocol.

We updated the page to make that assumption explicit. We also added a
diagram and some examples of how abstract identifier architecture has been
applied.

Thanks for pointing that out.

=Drummond 

> -----Original Message-----
> From: www-tag-request@w3.org [mailto:www-tag-request@w3.org] On Behalf Of
> Dan Connolly
> Sent: Thursday, September 18, 2008 9:35 AM
> To: www-tag
> Subject: abstract identifier: definition seems to be missing something
> 
> 
> I don't see how to make sense of this
> "MUST NOT resolve directly to a representation"
> in
>   http://wiki.oasis-open.org/xri/AbstractIdentifierArchitecture
>   last edited 2008-09-04 01:42:20
> 
> Consider:
> 
> a1 resolves to d1
> d1 contains c2
> c2 resolves to r2
> 
> So a1 is abstract, right?
> 
> But then I can make another resolution mechanism
> by composing the original "resolves to"
> with extracting concrete identifiers from
> descriptions and resolving them:
> 
> def resolves2(ident):
>    try:
>      r = resolve(ident)
>      return r
>    except OnlyDescriptionAvailable, d:
>      for c in d.concrete_identifiers():
>        try:
>          r = resolve2(c)
>          if r: return r
>        except:
>          pass
> 
> now resolves2(a) = r2. So I guess a
> isn't abstract after all.
> 
> Perhaps it would make sense to define
> abstractness _with respect to a given resolution mechanism_ a la:
> 
>   Identifier I for resource X is abstract with respect
>   to resolution mechanism L there
>   is no representation R of X where L resolves A to R.
> 
> All this is to say: whether an identifier is abstract
> or not is not a property of the identifier itself.
> Is info:abcdef abstract? Well, maybe today, but if
> the connection between that sort of identifier and
> representations of the resources they refer to
> is sufficiently valuable, someone will deploy a
> new resolution service, and suddenly info:abcdef
> is no longer abstract.
> 
> --
> Dan Connolly, W3C http://www.w3.org/People/Connolly/
> gpg D3C2 887B 0F92 6005 C541  0875 0F91 96DE 6E52 C29E
> 
Received on Monday, 22 September 2008 06:47:20 GMT

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