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Re: Working on glossary

From: Graham Klyne <Graham.Klyne@MIMEsweeper.com>
Date: Wed, 12 Sep 2001 14:29:29 +0100
Message-Id: <>
To: Martyn Horner <martyn.horner@profium.com>
Cc: pat hayes <phayes@ai.uwf.edu>, w3c-rdfcore-wg@w3.org

This debate has clearly gone beyond the original point that sparked it.  I 
should have changed the subject line -- I think it has more bearing on the 
nature of the model theory and its interpretations than the terminology 
(though use of terminology is part of our debate).

I don't think we're yet ready to propose a glossary clarification based on 
our exchange.  But I am hopeful something useful will emerge.


At 01:46 PM 9/12/01 +0200, Martyn Horner wrote:
>Since I contributed last, Pat and Graham have been going at it
>GK: http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Sep/0127.html
>PH: http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Sep/0130.html
>GK: http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Sep/0131.html
>PH: http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Sep/0132.html
>GK: http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2001Sep/0061.html
>I am grateful for the attention paid to this question.
>But, chaps, what I wanted to make was a glossary for the layperson which
>would help their initial understanding of some of our terms. I see,
>again, how dubious some of these terms are.
>Pat knows, from an exchange which came to nothing probably because I
>didn't express myself that well, that I am concerned about what I call
>the `temporal coherence' of stuff `on the Web'. This does seem to be an
>issue and, I can see, it's an issue which will not disappear just by
>defining (and redefining) the words we use. We have to offer to the
>newcomer a definition which allows for temporal variance without
>completely denying the usefulness and significance of the words.
>For those who haven't been following the thread, much of what has flowed
>past has been about the validity of defining a resource at all given its
>changing nature (whether incidentally in a changing world or
>functionally as a news service, for instance). Graham initially wanted
>to point out how separated the ideas of entity and resource were as in,
>for example, `today's weather forecast'. Then the discussion started...
>Just to quote some of GK's and PH's dialogue:
>Graham refers me (usefully, thanks) to
>http://www.w3.org/DesignIssues/Fragment.html where a distinction is made
>between a fragmentid-less URI which refers to a generic document and a
>fragmentided URI which refers to an identification within that document
>(and not just, as we know, a point in that document :-). Thus no '#'
>suggests just generic access and a '#' suggests an identification (eg,
>of a resource). Then he says:
>GK: `I find it difficult to unify the RDF idea of a resource (a thing
>that is identified) with the general Web idea of a resource (a thing
>that is queried or accessed) in light of these comments.'
>Me: So do I, Graham. So do I. I also find it difficult to generalize
>this distinction to non-document resources (you know the list, people,
>organisations, trees in the park, numbers,...)
>GK: (on the time-variance track) `The approach that I have seen adopted
>is to treat such things as sequences of values, or time-varying
>functions.' ... `Then, the resource can correspond to the current
>weather forecast, but its extension includes the set of all weather
>forecasts for all times;  the particular member of that extension one
>retrieves depends on when the retrieval is performed.'
>Me: Yes. This is why I think it's important to say that a `resource' is
>an entity identified by need (if you like), that the act of identifying
>it as a resource includes an understanding of such characteristics. This
>may not be its most precise definition but it would suggest for a new
>reader the role of the concept.
>PH: `As I understand it, the real-world objects *are* resources, so the
>idea of being retrievable on the web simply isn't applicable to
>resources in general.'
>Me: Retrievability is a characteristic of some resources, of course, but
>is not the crucial aspect of their identification even if the identity
>of a resource (`today's weather forecast') is expressed in terms of its
>retrieval. The resource is identified as `today's weather forecast' and
>its usefulness (the `need' for identification) is in its timeliness BUT
>the act of retrieval is not what makes it a resource.
>GK: `The alternative view I'm trying to offer here is that real-world
>objects are not resources, per se.  In addition to the octet-sequences
>that are web-retrievable entities, I'm suggesting that the real world
>objects are
>(also) part of the resource extension I mentioned previously, rather
>than the resource directly.'
>GK: `... but such (time-sensitive) semantics would be part of the
>semantics of a resource, about which the RDF model theory you have
>described seems to be agnostic.'
>Me: Ah-ha! Yes. This is how I think of it. The timeliness of information
>belongs in the semantic of that information but should not, in some
>sense, invalidate the identification of it as a resource. Again, a
>resource is an entity identified as required: the semantics may suggest
>that the entity will change.
>PH: `In the meantime however we could also just put this issue off to
>the future, and the current MT be thought of as kind of instantaneous
>time-slice of this extended temporal semantics.'
>Me: Oh, please, no. Or at least, let me get my glossary done with a nice
>clear message for the newcomer while we perhaps agonize about the real
>meanings. I don't think we have forced ourselves to consider that RDF
>refers to `a time-slice of an extended temporal semantic'...
>The ref
>that Graham includes is a good one, I admit. The idea of a duri: URN
>protocol to state that `I am referring to the page as it was then' is,
>of course, a valid one but it does not fit in with the requirements of a
>practical Semantic Web. Larry has it right but it's not going to help.
>It's great for putting in legal documents. However, the Semantic Web is
>going to have to cope with time-variant data and not just deliberately
>time-variant (like today's weather) or with time-variance created by
>retrieval or time-variance due to decay.
>Help. What shall we tell the novice? `Resource' (and its relationship to
>`entity') must be in the vocabulary of anyone starting to read the RDF
>documentation. I'd have thought it completely reasonable that some
>kernel of meaning can be attached to these words before such a reader
>has to face that the `true' meaning has certain unclear aspects.
>Do my definitions suffice, I still wonder...
>Martyn Horner <martyn.horner@profium.com>
>Profium, Les Espaces de Sophia,
>Immeuble Delta, B.P. 037, F-06901 Sophia-Antipolis, France
>Tel. +33 (0) Fax. +33 (0)
>Mob. +33 (0) Internet: http://www.profium.com

Graham Klyne                    MIMEsweeper Group
Strategic Research              <http://www.mimesweeper.com>
Received on Wednesday, 12 September 2001 09:33:21 UTC

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