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Re: [SKOS] Comments on SKOS Primer - other points

From: Antoine Isaac <aisaac@few.vu.nl>
Date: Tue, 13 Jan 2009 18:16:17 +0100
Message-ID: <496CCC61.2080804@few.vu.nl>
To: SWD Working Group <public-swd-wg@w3.org>

Thomas Baker a écrit :
> On Thu, Jan 08, 2009 at 08:01:43PM +0100, Antoine Isaac wrote:
>>>>      <p>By convention, mapping properties are used to represent
>>>>      links that have the same intended meaning as the "standard"
>>>>      semantic properties, but with a different scope. One might
>>>>      say that mapping relationships are less <em>inherent</em>
>>>>      to the meaning of the concepts they involve. From the point
>>>>      of view of the original designer of a mapped KOS, they might
>>>>      even sometimes be wrong.</p>
>>>>      <p>Mapping properties are expected to be useful
>>>>      in <em>specific</em> applications that use multiple,
>>>>      conceptually overlapping KOSs.  By convention, mapping
>>>>      relationships are expected to be asserted between concepts
>>>>      that belong to different concept schemes.  However, the use of
>>>>      mapping properties might also be appropriate in cases where
>>>>      someone other than its owner needs to enrich the semantic
>>>>      relationships within a particular concept scheme.</p>
>>>>      <p>The reader should be aware that according to the SKOS
>>>>      data model, the mapping properties that "mirror" a given
>>>>      semantic relation property are also sub-properties of it in
>>>>      the RDFS sense. For instance, <code>skos:broadMatch</code> is a
>>>>      sub-property of <code>skos:broader</code>.  Consequently, every
>>>>      assertion of <code>skos:broadMatch</code> between two concepts
>>>>      leads by inference to asserting a <code>skos:broader</code>
>>>>      between these concepts.</p> <hr>
> ...
>>> I like Tom's wording here.
>>> In fact, I would be tempted drop the first of these three paragraphs
>>> altogether. If I had no prior knowledge of SKOS, I would find the
>>> first two sentences ambiguous. The words "scope" and "inherent" are
>>> particularly difficult here. 
>> I can understand this. Would s/scope/application scope improve the 
>> situation? 
>>> And I'm not sure what value the third
>>> sentence adds. I.e. one hopes that cases where the KOS designer and
>>> the KOS mapper completely disagree about the nature of a mapping link
>>> would be very rare. A brief, casual mention such as this may leave the
>>> wrong impression, e.g. that these cases could be quite frequent.
>> In fact I expect that these cases would be quite frequent. If a KOS 
>> designer agreed that a mapping link between two concepts in her KOS fit her 
>> intent when creating the KOS, she would have created it as a standard 
>> semantic relationship then, wouldn't she?
> Well, maybe the project ended, or she simply overlooked the
> relationships or just ran out of time...  The point is here
> perhaps not so much about agreement or disagreement.
> Given the sub-property relationship between "mapping" and
> "standard" relationships, we are characterizing the difference
> between the two as being "conventional" in nature.
> What is the essence of that convention?  I think of a
> "standard" relationship as asserting "A skos:broader B",
> where the corresponding "mapping" relationship would assert
> something like: "I'm not the owner or designer of the concept
> scheme, but A skos:broader B".
> Maybe it's like being on a "tu" or "vous" basis with
> the concept scheme -- a cultural distinction that sends
> signals without altering the basic (second-person-singular)
> relationship :-)
> The argument could run as follows: Ideally, we should be able
> to tell from provenance information who said what, but in
> practice, Semantic Web data is often merged in simple ways that
> obscure the origins of assertions.  The distinction between
> "mapping" and "standard" relationships is one of etiquette --
> directly asserting "standard" relationships sends the message
> that the asserter considers herself qualified to define the
> relationship in a standard way.  For everyone else, the polite
> thing is to assert a "mapping" relationship.
> So I'd be inclined to replace the first paragraph with
> something else but would first like to hear whether we agree
> on this way to characterize the distinction.

I think the sentence below is really helpful:

> The distinction between
> "mapping" and "standard" relationships is one of etiquette --
> directly asserting "standard" relationships sends the message
> that the asserter considers herself qualified to define the
> relationship in a standard way.

Note that whatever happens (I am far from stubbornly attached to my own text, which I know is rather suboptimal :-/) I am strongly in favor of having a paragraph there. Which is inline with the resolution we made at the Washington F2F [1]:

RESOLUTION: 1. keep the mapping vocabulary broadMatch, narrowMatch, 2. broadMatch, narrowMatch, etc. are rdfs:subPropertyOf broader, narrower, 
[...] 4. there is some text about cultural conventions explaining where we expect broadMatch to be used, 5. by convention, mapping properties are only used to link concepts in different schemes, [...]


[1] http://www.w3.org/2008/05/06-swd-minutes.html#item04

> Tom
Received on Tuesday, 13 January 2009 17:16:51 UTC

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