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Joe English wrote:
>Bullard, Claude L (Len) wrote:
>
>
>>That's the critical observation for this and many other
>>threads that rely on ontological commitment to sustain
>>communications.
>>
>>Would anyone care to compare that to URIs as a unit of
>>information:
>>
>>1. Is a URI a resource?
>>
>>
>
>No. There is no such thing as a "resource".
>
>To elaborate on that: There are two groups that have
>spent a lot of time and energy trying to figure out
>what a "resource" is, and both have come to the same
>conclusion: We don't know what a "resource" is, and we
>don't really care either.
>
>For lack of a better name I'll call these "the REST camp" and
>"the RDF camp". In the REST camp's worldview, "resources"
>are formally and explicitly left undefined --
>
Hmm...IMHO, Roy has been pretty specific about what a resource is:
" More precisely, a resource /R/ is a temporally varying membership
function /M/_R /(t)/, which for time /t/ maps to
a set of entities, or values, which are equivalent. The values in the
set may be /resource representations/ and/or
/resource identifiers/."
http://www.ics.uci.edu/~fielding/pubs/dissertation/rest_arch_style.htm#sec_5_2_1_1
With GET you invoke the membership function.
Are you maybe confusing 'concept' (a humans interpretation what is being
"mapped to a set of entities")
with 'resource'?
Jan
>you can GET
>a representation of one, or you can POST an entity to one,
>or do a number of other things, but you can never get your
>hands on the resource itself. It's a convenient fiction.
>
>In the RDF camp's worldview, you don't do anything with
>resources either except Identify them and Describe them.
>REC-rdf-mt even goes so far as to say that:
>
>| The semantics does not assume any particular relationship
>| between the denotation of a URI reference and a document
>| or Web resource which can be retrieved by using that URI
>| reference in an HTTP transfer protocol, or any entity which
>| is considered to be the source of such documents. [...] The
>| things denoted are called 'resources', following [RFC 2396],
>| but no assumptions are made here about the nature of resources;
>| 'resource' is treated here as [...] a generic term for anything
>| in the universe of discourse.
>
>In other words: we don't know, and we don't really care either.
>
>
>
>
>>2. If it is a resource, what operations are significant?
>>
>>
>
>See above. There is no such thing as a resource.
>
>
>
>
>>3. Are URIs ever ambiguous?
>>
>>
>
>Yes, but only if you go out of your way to make them so.
>
>You can follow the REST camp and treat them as mostly-opaque
>identifiers, perform GETs, POSTs, and DELETEs, and never
>worry at all about the shape of the URI itself except to
>ensure that it's syntactically valid, and maybe compose
>it with a relative URI here and there. The last two
>are purely syntactic operations. Do two different URIs
>refer to the same resource? Who cares? It's not important.
>
>Or you can follow the RDF camp, and treat them as opaque
>identifiers that can be compared for equality, again
>a purely syntactic operation. Do two different URIs
>denote the same resource? Only if there's an assertion
>somewhere that says they do. Otherwise, who cares? It's
>not important.
>
>Or you can follow the xml-dev approach, and continue
>to spend time and energy trying to figure out how many
>angels can dance on the head of a pin, and whether they're
>really dancing on the same pin or not.
>
>
>
>--Joe English
>
> jenglish@flightlab.com
>
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--
Jan Algermissen
Consultant & Programmer
http://jalgermissen.com
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