Abel2007enabling presented by Tim Lebo 25 sept 2008 Jesse Weaver

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• Question is for the Presentation: Abel2007enabling presented by Tim Lebo 25 sept 2008
• Question is asked by: Jesse Weaver
• The Question is: ONE: How does this approach apply to inferred triples? For example, consider PB subPropertyOf PA. If a user is denied triples using PA but has access to triples using PB, he/she may be able to effectively "access" (via inference) some of the PA triples. TWO: Also, perhaps the user shouldn't be able to see triples that are inferred from triples to which they do not have access. Is this accounted for?

Response:The policies that reflect this situation would be: deny(?s, ex:PA, ?o) <- {}, allow(?s, ex:PB, ?o) <- {}. The semantics of rdfs:subPropertyOf state: if ex:PB rdfs:subPropertyOf ex:PA and ?s ex:PB ?o, then ?s ex:PA ?o. This says that when the ex:PB property is used, so is the ex:PA. When ex:PA is used, however, ex:PB is not. In this case, I do not see how a user "may be able to effectively 'access' some of the ex:PA triples." TWO: You are correct, there may exist triples in the repository that were entailed from triples to which the user may not have access. This is a result of the disjoint nature of the policy rules and the repository. It would be an interesting investigation to incorporate the policy rules during the inferencing process at the triple store.warning.pngString representation The policies that reflect this situation w […] e inferencing process at the triple store. is too long.