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HTTP inference rules [was: AWWSW minutes from today]

From: Booth, David (HP Software - Boston) <dbooth@hp.com>
Date: Sun, 10 Feb 2008 09:00:03 +0000
To: "Williams, Stuart (HP Labs, Bristol)" <skw@hp.com>
CC: "public-awwsw@w3.org" <public-awwsw@w3.org>
Message-ID: <184112FE564ADF4F8F9C3FA01AE50009DED1018129@G1W0486.americas.hpqcorp.net>

> From: Williams, Stuart (HP Labs, Bristol)
> [ . . . ]
> > From: David Booth
> [ . . . ]
> > Thanks for your comments on
> >>> http://esw.w3.org/topic/AwwswDboothsRules
> [ . . . ]
> > Yes, I was trying to say that the app knows to use the
> > follow-your-nose principle, but I guess I should have worded
> > it better.  I've hopefully improved the wording now.  Check
> > the wiki again and see what you think:
> > http://esw.w3.org/topic/AwwswDboothsRules
> >
> The page still speaks of assumptions... I was trying to say that what
> you are speaking of is not an assumption, I believe that its is more
> axiomatic in the architecture of the web.

Which assumptions do you mean?  Can you be specific?

> [ . . . ]
> > The 303 rule is separate, a little farther down the page.
> >
> I was speaking of the comment line in the sample input... any
> way you've
> eliminate that mention of 301, 302 and 307, so 303 is no longer
> noticeable absent,

Yeah, that was a bad copy-and-paste artifact.  :)

> [ . . . ]
> >> # And we'll assume that in parsing the above triple, the app
> >> *also* automatically asserted the following triple:
> >> # <http://dbooth.org/2008/httpinf/moon.rdf#themoon> log:uri
> >> #
> >> "http://dbooth.org/2008/httpinf/moon.rdf#themoon"^^xsd:anyURI .
> >>
> >> This is an obvious tautology... and as such harmless...
> >>
> >
> > I don't think it is a tautology.  AFAICT this is a
> necessary assumption, since in the RDF semantics,
> <http://dbooth.org/2008/httpinf/moon.rdf#themoon> denotes a
> resource. The URI is at the syntactic level, not semantic.
> How would any rules otherwise know what URI had been used to
> denote that resource?
> >
> "The thing denoted by the URI 'xxx'  is denoted by the URI 'xxx'."
>
> Looks like a straight tautalogy to me.

It sounds like you are confusing syntactic and semantic domains.  Semantically <http://dbooth.org/2008/httpinf/moon.rdf#themoon> denotes a particular resource, and nothing more.  That exact same resource could just as well be denoted by some other URI, such as http://example/fribjam , in which case the above could have been written as:

  <http://example/fribjam> log:uri
      "http://dbooth.org/2008/httpinf/moon.rdf#themoon"^^xsd:anyURI .

which no longer looks like a tautology even though it would have the *exact* same semantics.

> [ . . . ]
> >> 2) I think this will quickly get messy with some means to
> >> distinguish inferences derived from different responses. Over
> >> time the multipicity of different responses and monotonic
> >> assertions inferred from them may lead to inconsistent KBs.
> >>
> >
> > Correct.  It does not prevent a URI owner from issuing
> > conflicting URI declarations at different points in time,
> > thus causing a "URI collision":
> > http://www.w3.org/TR/webarch/#URI-collision
> > The architecture does not prevent URI collisions, but
> > admonishes URI owners and users to avoid them.   If an owner
> > issues conflicting URI declarations, users are likely to
> > avoid using the URI.
> >
> I'm not talking about URI-collision - I taking about a KB which has
> become inconsistent... where it is possible to prove that there are no
> intepretations which satsify the model.
> [ . . . . ]

Aren't you talking about different URI declarations being served at different times, thus causing inconsistencies over time?  If so, then the URI is being declared differently at different times, i.e., the same URI is used to denote different things at different times, which is one form of URI collision.  (I.e., the same party is using the URI to denote different things at different times, rather than different parties using the URI to denote different things.)  If that isn't what you are talking about then please explain.



David Booth, Ph.D.
HP Software
+1 617 629 8881 office  |  dbooth@hp.com
http://www.hp.com/go/software

Opinions expressed herein are those of the author and do not represent the official views of HP unless explicitly stated otherwise.
Received on Sunday, 10 February 2008 09:01:05 GMT

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