- From: Michael Schneider <schneid@fzi.de>
- Date: Tue, 2 Sep 2008 10:48:39 +0200
- To: "Ian Horrocks" <ian.horrocks@comlab.ox.ac.uk>
- Cc: "W3C OWL Working Group" <public-owl-wg@w3.org>
- Message-ID: <0EF30CAA69519C4CB91D01481AEA06A0B9868F@judith.fzi.de>
[related to ISSUE-130 and ISSUE-131 (Conformance and OWL RL Unification)] Hi! I have read the Conformance proposal at <http://www.w3.org/2007/OWL/wiki/Conformance> It's a clearly written document. I have several comments/questions. * 1.1.1. """ Any RDF/XML document is an OWL 2 Full ontology document. """ I suggest to replace "RDF/XML document" by "RDF document" or "RDF graph". Whether something is a Full ontology should not depend on a specific RDF serialization. * 1.1.1. """ An OWL 2 Full ontology document is an OWL 2 RL ontology document iff it can be successfully parsed using the canonical RDF parsing process and the resulting ontology in the functional-style syntax satisfies all the restrictions on OWL 2 RL ontologies """ Now I understand that one of the purposes of the (so far) OWL RL DL syntax is to define /syntactic/ conformance. For example, the following RDF graph (aka OWL 2 Full ontology) is /not/ a syntactically conformant OWL RL ontology: ex:C rdfs:subClassOf _:x _:x owl:unionOf (SEQ ex:D1 ex:D2) because, after the reverse mapping, it would not meet the RL syntax restrictions. I'm personally fine with this. * 1.2.1. """ An OWL 2 entailment checker takes as input two OWL 2 ontology documents O1 and O2 """ Isn't it better to talk about "two /imports-closed collections of/ OWL 2 ontology documents"? * 1.2.1. """ and either the Model-Theoretic Semantics [OWL 2 Semantics] or the RDF-Based Semantics [OWL 2 RDF-Based Semantics] """ I just want to state that the RDF-Based Semantics is also a model-theoretic semantics, so this is not a useful distinction criterion. * 1.2.1 """ An OWL 2 entailment checker returns one word, being True, False, or Unknown. """ Perhaps, it's better to talk about "result" instead of "word". * 1.2.1 """ An OWL 2 Full entailment checker is an OWL 2 entailment checker that takes RDF/XML documents as input """ Again "RDF/XML". But here, one can simply write "OWL 2 Full ontology documents", because this term has already been defined elsewhere, and it would also be better in line with the rest of the "entailment checker" definitions in this section. * 1.2.1 Analog for "OWL 2 RL entailment checker". But my question is: Should it be "OWL 2 /Full/ ontology documents" or "OWL 2 /RL/ ontology documents"? * 1.2.1 """ An OWL 2 RL entailment checker [...] MUST return True only when O1 entails O2, and it must return False only when FO(O1) ? R does not entail FO(O2) under the standard first-order semantics """ Just to be clear: This means that there can be two conformant OWL 2 RL entailment checkers C1 and C2, where for the same query "G_L |= G_R ?" C1 answers "False" (because G_R does not follow from G_L via the rules), while C2 answers "True" (because G_R follows from G_L via the Full semantics). I suggest that we state it explictly that this is intended. Otherwise people might get confused and think that this is a bug. * 1.2.1: "terminating and complete entailment checker" """ reject the input as syntactically invalid """ I don't understand what this means in the case of OWL RL. According to 1.1.1, RDF seems to be the reference syntax, but RDF graphs are only said to be "RL conformant", if they can be successfully parsed into Functional Style syntax and satisfy the RL restrictions. So I wonder whether all RDF graphs or only those matching the RL restrictions (the "syntactically OWL RL conformant ontology documents"!) are syntactically valid input to an OWL RL entailment checker. Perhaps it is meant that an OWL RL entailment checker MAY reject syntactically non-conformant OWL 2 RL documents, but if it accepts them, then it has to provide the True/False/Unknown behavior as stated (e.g. it must not say "True", if the OWL Full semantics do not entail). I would like to see some clarification here. * 1.2.1: """ An OWL 2 entailment checker is terminating if, given sufficient memory resources """ I think that two slight clarifications are needed here: (1) Is by "given sufficient memory resources" meant that the amount of memory is determined "a priorily" by the problem size? Or that memory can be appended on demand, such as in the case of a printer running out of paper? (2) Definition of "completeness": Does this definition allow an input on which the entailment checking process does not terminate? Or is the definition of termination already part of the definition of completeness? Best, Michael >-----Original Message----- >From: Ian Horrocks >Sent: Monday, August 25, 2008 1:27 PM >To: public-owl-wg Group WG >Subject: ISSUE-130 / ACTION-194 Come up with a proposal for conformance > > >A draft proposal is now available in the Wiki [1]. The idea is that >this would become the conformance section in the Test document [2]. > >Ian > >[1] http://www.w3.org/2007/OWL/wiki/Conformance >[2] http://www.w3.org/2007/OWL/wiki/Test#Conformance -- Dipl.-Inform. Michael Schneider FZI Forschungszentrum Informatik Karlsruhe Abtl. Information Process Engineering (IPE) Tel : +49-721-9654-726 Fax : +49-721-9654-727 Email: Michael.Schneider@fzi.de Web : http://www.fzi.de/ipe/eng/mitarbeiter.php?id=555 FZI Forschungszentrum Informatik an der Universität Karlsruhe Haid-und-Neu-Str. 10-14, D-76131 Karlsruhe Tel.: +49-721-9654-0, Fax: +49-721-9654-959 Stiftung des bürgerlichen Rechts Az: 14-0563.1 Regierungspräsidium Karlsruhe Vorstand: Rüdiger Dillmann, Michael Flor, Jivka Ovtcharova, Rudi Studer Vorsitzender des Kuratoriums: Ministerialdirigent Günther Leßnerkraus
Received on Tuesday, 2 September 2008 08:49:23 UTC