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RE: exploring ambiguity via the "something-which-has" URI scheme

From: <Patrick.Stickler@nokia.com>
Date: Wed, 7 May 2003 13:43:17 +0300
Message-ID: <A03E60B17132A84F9B4BB5EEDE57957B01B90D8E@trebe006.europe.nokia.com>
To: <GK@ninebynine.org>, <sandro@w3.org>
Cc: <uri@w3.org>, <phayes@ai.uwf.edu>



> -----Original Message-----
> From: ext Graham Klyne [mailto:GK@ninebynine.org]
> Sent: 07 May, 2003 12:56
> To: Stickler Patrick (NMP/Tampere); sandro@w3.org
> Cc: uri@w3.org; phayes@ai.uwf.edu
> Subject: RE: exploring ambiguity via the "something-which-has" URI
> scheme 
> 
> 
> [Nothing of relevance to RFC2396bis herein]
> 
> At 11:47 07/05/2003 +0300, Patrick.Stickler@nokia.com wrote:
> >I think that Pat and I actually are in more agreement about this
> >than disagreement, and in fact the disagreement reflected above
> >does not exist but arose out of my misuse of the terminology.
> >
> >My key point is that, for the SW (and not any application using RDF
> >that is not considered to participate in the SW) all parties must
> >agree upon denotations of a given URI which are compatible, even if
> >not identical.
> 
> I think one of the continuing terminological problems is this 
> (ab)use of 
> "denotes".  In the context of RDF formal semantics, and model 
> theoretic 
> semantics generally (I think), the denotation of a URI is a 
> feature of a 
> particular interpretation, and different interpretations may assign 
> different denotations.  This is irrespective of what we may intend a 
> particular URI to mean or represent.
> 
> As for the intended meaning, I'm still trying to reconcile 
> the ideas that 
> we often think we know what a name is intended to represent, 
> yet, as Pat 
> says, language in general and RDF in particular does not provide any 
> workable mechanism to fix a single meaning for a name.
> 
> I think there's an interesting parallel between the view of URIs as 
> resource identifiers and formal semantics by model theory.  
> URIs are used 
> to identify some (loosely specified) underlying concept of a 
> resource that 
> yields certain representations under certain circumstances.  Those 
> representations are all we actually get to observe -- 
> anything we may wish 
> to know about a resource must be elicited in terms of such 
> representations.   Model theoretic semantics likewise does 
> not fix the 
> exact meaning (denotation) of a name, but allows us to constrain its 
> meaning by limiting interpretations to those which match 
> certain statements 
> we may choose to make.
> 
> What these seem to have in common is a limiting case.  The 
> more we say 
> about a resource, the more "closely" it may be constrained to some 
> asymptote of meaning.  The more representations of a resource that we 
> examine, the more we may learn about its "essential invariant 
> characteristics".  But certaintly is elusive.
> 
> (Example:  let f(x) = sin(x)/x.  What is the value of f(0)?  We can't 
> evaluate f(0) directly as it involves a division of zero by 
> zero; but if we 
> consider the region about x=0, then a credible argument can 
> be sustained 
> that f(0)=1, for x in radians, because Lim[x->0]f(x)=1.)
> 
> In the mathematics I've been exposed to, the concept of a 
> limit is strongly 
> related to some idea of a metric, so that we can talk in 
> terms of relative 
> closeness of pairs of values.    But there is no obvious metric for 
> denotations of a resource.  (At this point I muse about 
> things I don't 
> really understand, such as the theoretical work underpinning 
> aspects of 
> denotational semantics of programming languages ala 
> Scott/Strachey, also 
> ideas of subsumption as appear in description logics...)
> 
> So can it make sense to think of the intended meaning of a 
> name as a kind 
> of region of meaning, bounded by those things we can observe 
> or say about a 
> resource?  Ambiguity remains, but within bounds that we trust 
> will not 
> affect the results we wish to achieve in using a name.  There 
> is a kind of 
> presumption here that one can make more observations, assert more 
> constraints, to progressively constrain the nature of a 
> resource in question.
> 
> #g

Thanks Graham. This fits well with how I've been viewing the matter.

Even if, according to the MT, the denotation/interpretation of a 
given URI may differ, what counts for the SW is that those 
denotations/interpretations be compatible.

Incompatible denotations/interpretations are what harm the SW.

Patrick
Received on Wednesday, 7 May 2003 06:43:23 GMT

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