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Re: Dinamic hasTopConcept property

From: Leonard Will <L.Will@willpowerinfo.co.uk>
Date: Thu, 3 Dec 2009 23:11:57 +0000
Message-ID: <RL904MN9WEGLFAV9@mail.willpowerinfo.co.uk>
To: public-esw-thes@w3.org
On Thu, 3 Dec 2009 at 17:17:43, Juan Antonio Pastor Sánchez 
<pastor@um.es> wrote
>Hello everyone,
>
>I am developing an application to manage concept schemes, based on SKOS. My
>question is about the hasTopConcept property. In my opinion this property
>should be generated dynamically (by inference) during the query of the
>concept scheme (only for viewing and browsing purposes). As indicated in
>SKOS-Reference:
>
>"The property skos: hasTopConcept is, by convention, used to link a concept
>to the SKOS concept scheme (s) which are topmost in the hierarchical
>relations for that scheme."
>
>That is, a Top concept would be a concept of a hierarchy that did not have
>any one broader concept. Therefore, It is not necessary to explicitly define
>a concept such as Top concept. Thus, the tasks of managing the scheme
>concept could be simplified.
>
>This interpretation would be correct?

I have not checked the detail of the SKOS approach, but in the draft of 
ISO25964-1 we provide for noting "top concept" in two distinct cases.

The draft of that standard, which you can read and comment on (after 
free registration) at <http://drafts.bsigroup.com/> contains the 
following clause:

-----------------------------------------------

15.2.13 Top level concepts

Clause 12 makes brief mention of “Top Terms” i.e. terms representing 
top concepts, as an optional feature of alphabetical displays and single 
term displays, linking a concept to the top concept of the hierarchy in 
which it occurs. The class TopLevelRelationship enables this.

Clause 14.9 b) also recommends a browse capability that starts by 
presenting editors with a list of top terms. The attribute topConcept 
addresses this, specifying that a concept is at the top of a hierarchy, 
i.e. it has no broader concepts. This makes it easier, on importing a 
thesaurus, to pick out all the top level concepts from which to build a 
navigational tree.

----------------------------------------------

The two elements are: (a) a relationship between any concept and the 
concept(s) at the top of whatever hierarchy/ies it is found in; and (b) 
a Boolean attribute of a concept that indicates whether it is a "top 
concept", i.e. that it has no broader concepts.

It is true that both of these are really redundant, as they can be found 
by (a) checking for broader concepts and (b) working up a hierarchy as 
far as possible. We included them as optional elements because some 
systems might find it more efficient to store them rather than to work 
out their values every time they are needed.

Top concepts may coincide with the names of facets in a type of 
thesaurus where hierarchies are combined as far as possible, so that 
there are only a comparatively few top concepts defining distinct and 
mutually exclusive "fundamental categories". It is important in some 
systems to know what facet a concept belongs to.

If, alternatively, a thesaurus has a large number of small hierarchies, 
it may be convenient when generating displays to be able to quickly pick 
out all top level concepts. Displaying a concept's top level ancestor is 
also sometimes helpful in identifying context and thus clarifying scope, 
supplementing information provided by other relationships and the scope 
note, if any.

Leonard Will

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Received on Thursday, 3 December 2009 23:17:50 UTC

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