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Re: Some thoughts on the semantics of domain and range

From: Graham Klyne <GK@Dial.pipex.com>
Date: Thu, 14 Sep 2000 11:05:15 +0100
Message-Id: <4.3.2.7.2.20000914105735.00bc3100@pop.dial.pipex.com>
To: "Lee Jonas" <ljonas@acm.org>
Cc: <www-rdf-interest@w3.org>
At 10:24 AM 9/14/00 +0100, Lee Jonas wrote:
[...]
>In summary:
>* objectivity about all RDF statements on the entire Web is going to be
>impossible - subjectivity (relative to a 'frame of reference') is the only
>recourse, therefore conclude stuff based on your viewpoint.

Well, TimBL and others have asserted that the Web should have a common 
"proof language", even if individual statements are interpreted w.r.t. some 
"frame of reference"  (context?).

If I understand the concept correctly, this "proof language" embodies some 
set of rules whereby one can determine the validity or otherwise of some 
chain of reasoning, based on some set of assertions, including assertions 
about the nature of the logic of the assertions.  So, for example, fuzzy 
logic reasoning can be described by some "proof language" assertions, and 
then fuzzy logic reasoning can be validated using the proof language in 
concert with those assertions.

I think the RDF/RDFS core should focus on features needed for that common 
proof language, which means being able to draw some useful inferences 
independent of frame of reference.  Conjunctive semantics _seems_ to be 
consistent with that goal.

>* rdfs:domain is _very_ useful as it currently stands for asserting model
>validity (albeit based on your current frame of reference).

This, I cannot and do not dispute.  Whether it belongs in the core, I question.

>* although rdfs:range could be restricted to at most one per Property
>definition given a frame of reference, it is far more useful to allow
>multiple disjunctive semantics here as well for more refined validity
>assertions.

I agree about avoiding "restriction to one" ... just not the suggested 
semantics.

#g

------------
Graham Klyne
(GK@ACM.ORG)
Received on Thursday, 14 September 2000 06:06:22 GMT

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