W3C home > Mailing lists > Public > semantic-web@w3.org > November 2012

Re: rdf semantics and timelessly true

From: Pat Hayes <phayes@ihmc.us>
Date: Wed, 14 Nov 2012 08:27:25 -0800
Cc: Sergey Larionov <s.larionov@rks.karelia.ru>, Semantic Web <semantic-web@w3.org>
Message-Id: <D27DE344-BE56-4841-AEB7-A534EDE78EAA@ihmc.us>
To: nathan@webr3.org

On Nov 14, 2012, at 8:03 AM, Nathan wrote:

> Hi Pat,
> 
> Pat Hayes wrote:
>> Its not impossible, and in a strong sense this is required by the current RDF semantics, which treats all RDF assertions as timelessly true.
> 
> Can you refine / expand on this please? I'd presumed RDF to have no consideration of time - e.g time-less; as opposed to being true for all time (timeless).
> 
> TIA,
> 
> Nathan

Yes, time-less is a better way to put it. But it is so because URIreferences are assumed (and I know this is an idealization, but...) to be timeless in how they refer. Section 1.2 says:  "... the semantics simply assumes that ... a single URI reference can be taken to have the same meaning wherever it occurs. Similarly, the semantics has no special provision for tracking temporal changes. It assumes, implicitly, that URI references have the same meaning whenever they occur."

In other words, no counters allowed. 

Pat


> 
> 

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Received on Wednesday, 14 November 2012 16:28:01 GMT

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