Graph Features SWS

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• Question is for the Presentation: Theoharis2008graph presented by Tim Lebo 4 dec 2008
• Question is asked by: Ankesh Khandelwal
• The Question is:

1. Authors quote numbers from a reference to show that the number of OWL ontologies is 6 times lesser than RDFS ontologies. I bet there are very few OWL ontologies that use cardinality restrictions. Inspite of these statistics I am tempted to ask- wouldn't it be relevant to discuss cardinality restrictions in the context of the work in this paper. Cardinality restrictions (special case- functional properties) on a property, relate a class (RESTRICTION) to the range of the property. In addition they restrict the out-degree (total-degree) which is very relevant here. Do you think the same, and if possible how do you think cardinality restrictions can be accounted for?
2. This probably should have come before the previous question, but since first question led me to think of this one, i keep it second. Many properties are intended to take multiple values. For example a property that relates team to its members, say hasMember. If authors would have considered instance data this would have been accounted for. Therefore it may not be enough to consider a single edge <team, hasMember, players> for total-degree estimations. Do you also see that as a problem? How do you think we can resolve this issue, if there is one?
3. This question is also in context of those minority ontologies in OWL. I could understand that in the case of allValuesFrom, say C = AllValuesFrom(P,A), we can have an edge <C, P, A>. However, it's not clear from the paper that how the authors take into account someValuesFrom feature of OWL.
4. What about property hierarchy? It's an RDFS feature. My personal feeling is that its inclusion shouldn't affect the VR and CCDF values for total-degrees (do you think so?). Still.. do you think property hierarchies should have been discussed (or considered) by the authors?

1. You make a very valid point that just being an "OWL" ontology does not mean that you actually use all of the constructs (is typing classes to owl:Class sufficient for being "OWL"?). I would like to find out the answer to your bet, but I wouldn't place any myself. Why do you think that cardinality restrictions are not used? (TBD...)
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