ISSUE-182 draft response

Hi all,

Here's a draft response to Michael on [ISSUE-182], let me know what you 
think. Note *this is just a draft, not the actual response* -- I'll wait 
for feedback from the WG before replying formally to
to Michael. (Michael: if you're lurking on this list feel free to post 
your thoughts at any time.)


Dear Michael,

Thank you for your comments [1]:

2. Index terms

An important part of many classification systems is an index, in the
case of the DDC its "Relative Index". Index terms associated with a
given class generally reflect several of the topics falling within the
scope of that class. There is no easy way of modeling this relationship
in SKOS:

616 Diseases

Index terms:
   Clinical medicine
   Internal medicine
   Physical illness--medicine

Currently, a possible workaround is to construct the complete Relative
Index as a separate skos:ConceptScheme and relate the concepts in these
two independent schemes by using mapping relations:

skosclass:hasIndexTerm rdfs:subPropertyOf skos:closeMatch .

skosclass:isIndexTermOf rdfs:subPropertyOf skos:closeMatch ;
  owl:inverseOf skosclass:hasIndexTerm .

<class/616> a skos:Concept ;
  skosclass:hasIndexTerm <index/Clinical%20medicine> ;
  skos:inScheme <classification> .

<index/Clinical%20medicine> a skos:Concept ;
  skosclass:isIndexTermOf <class/616> ;
  skos:inScheme <index> .

This seems to be a satisfactory best-practice solution in this case, but
it has broader implications as index terms are just one instance of
Class-Topic Relations


I faced a similar case once. We just did not represent these indexing 
links at the time, but if it had been a matter of life or death I would 
have used (specialization) of mapping properties, as you proposed. The 
solution you propose is I think very statisfactory!
Another option would be to use dc:subject (or a specialization of it) : 
after all, indexing of concepts or classes by other concepts or classes 
can be likened to indexing of douments (or general resources) by 
concepts or classes!

But our concern with your comment is that its scope might be limited, 
considering the whole context of KOS practice. We had indeed not 
identified that kind of situation in our Use Cases and Requirements 
document [2], even for the classification case we had at hand (which was 
UDC [3]).

We actually would welcome your opinion, whether this is a big 
shortcoming or not. But we hope you are able to live with the current  

In fact if you believe this situation is more common than what we 
currently think, we'd also encourage you to publish a brief best 
practice note and inform the SKOS community via the mailing list. We'd 
also be more than happy to set up a "SKOS community best practices" wiki 
page to collect links to such statements! Note that in your specific 
case, all the elements that you have brought in [1] could be a useful 
addition to the practices presented in [4]...

Best regards,



Received on Friday, 17 October 2008 08:15:20 UTC