From: Antoine Zimmermann <antoine.zimmermann@emse.fr>

Date: Thu, 13 Sep 2012 18:50:43 +0200

Message-ID: <50520EE3.9010002@emse.fr>

To: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>

CC: RDF WG <public-rdf-wg@w3.org>

Date: Thu, 13 Sep 2012 18:50:43 +0200

Message-ID: <50520EE3.9010002@emse.fr>

To: "Peter F. Patel-Schneider" <pfpschneider@gmail.com>

CC: RDF WG <public-rdf-wg@w3.org>

Le 13/09/2012 03:08, Peter F. Patel-Schneider a écrit : > I don't think that example 2.16 is correct. I'm afraid you're right. > It seems to me that any dataset with a consistent default graph is > consistent. I consider this to be good news. > Any interpretation of the default graph can be extended to an > interpretation of the dataset by mapping every resource to inconsistent > graphs. This trivially satisfies "IGEXT(/I_d /(/n/)) is defined and > /E/-entails g" as an inconsistent graph entails every graph. Correct. So there must be at least 2 of the graphs in the graph extensions of :n, :m and :o that are inconsistent, but it's not possible to know which ones. Here is another test case: { :n owl:sameAs :m } :n { :s :p :o } :m { :x owl:differentFrom :x } OWL-dataset-entails: :n { :t owl:sameAs rdf:type } > I don't think that this means that 2.16 is not tricky. There is some > interaction. However, this means that named graphs are not independent > from each other. In fact, there is a much easier situation showing that > named graphs are not independent, namely 2.13 T11.2 Similarly, it means > that named graphs are not independent from the default graph. > > It is also the case that an inconsistent default graph makes the named > graphs irrelevant. It makes the dataset inconsistent, which is fortunate. > This last is, I think, a particularly strong point against providing > this sort of semantics at all. By "this last", what do you mean? This last test case (T14.1) or this last sentence that you wrote above? I think you mean the former (if it's the latter, I don't see why). Do you think that, if the graphs--named and default--were independent, it would be acceptable? That's the alternative proposal where IGEXT maps IRIs to graphs, instead of resources to graphs. But even with IGEXT mapping resources, I find the test case to be even more satisfying if it's consistent. It makes it easy to implement a reasoner in that case. Take a reasoner for entailment regime E. Check if any two of the graph IRIs denote the same thing in the default graph. For each group of owl:same graph IRIs, reason on the merge of the graphs in the group, using the E-reasoner. AZ > > > peter > > -- Antoine Zimmermann ISCOD / LSTI - Institut Henri Fayol École Nationale Supérieure des Mines de Saint-Étienne 158 cours Fauriel 42023 Saint-Étienne Cedex 2 France Tél:+33(0)4 77 42 83 36 Fax:+33(0)4 77 42 66 66 http://zimmer.aprilfoolsreview.com/Received on Thursday, 13 September 2012 16:50:34 GMT

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