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RE: SKOS exactMatch Inclusion - a question concerning ISSUE75

From: Vladimir Alexiev <vladimir.alexiev@ontotext.com>
Date: Fri, 18 Oct 2013 16:27:25 +0300
To: "'Hong Sun'" <hong.sun@agfa.com>
Cc: "'Giovanni Mels'" <giovanni.mels@agfa.com>, "'Jos De Roo'" <jos.deroo@agfa.com>, <public-esw-thes@w3.org>
Message-ID: <00a801cecc05$c933efd0$5b9bcf70$@alexiev@ontotext.com>
As Johan points out, the SKOS spec is clear that nothing follows from exactMatch, nor the other way around.
exactMatch is an equivalence property (transitive and symmetric), but it doesn't follow that it's "composable" with any other transitive property like broaderTransitive.

I find this unfortunate. Here are some more considerations:

- broadMatch allows you to graft a tree from one thesaurus to another. 
But exactMatch doesn't interlink the neighborhoods of the two concepts in any way :-(
In that sense, it's WEAKER than broadMatch 

- SKOS allows "broader" cycles: http://www.w3.org/TR/skos-reference/#L2484. In such case I'd say that all the concepts in the cycle are exactMatch...
Another way of saying the same is: if <c1 broader c2> and <c1 narrower c1> then c1 <exactMatch c2>

- if <c1 foaf:focus o> and <c2 foaf:focus o> then I think should follow <c1 exactMatch c2>.
  I proposed this half a year ago, Antoine called it a "co-denotation axiom" and found it reasonable.
-- by the semantics of sameAs, the same consequence would follow from
   <c1 foaf:focus o1> and <c2 foaf:focus o2> and <o1 sameAs o2>

But like any other standard, SKOS is the result of some compromises: I guess the negators and doubters of such inferences won over in this case.

However, this does not stop you from defining yourself such axioms in your dataset. E.g.
   skos:broader owl:propertyChainAxiom (skos:broader skos:exactMatch).
Or using the PROTON ontology:
  skos:broader ptop:transitiveOver skos:exactMatch.
Received on Friday, 18 October 2013 13:27:49 UTC

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