Alan is concerned about citation of our meeting minutes. See message Michael Zakharyaschev <email@example.com
To: Michael Zakharyaschev <firstname.lastname@example.org
Subject: [LC response] To Roman Kontchakov & Michael Zakharyaschev
Dear Roman and Michael,
Thank you for your comment
on the OWL 2 Web Ontology Language last call drafts.
Your comment is closely related to the one by Maurizio (see http://lists.w3.org/Archives/Public/public-owl-comments/2009Jan/0014.html) and Ivan (see http://www.w3.org/mid/49881F19.email@example.com).
The working group has decided to implement the editorial changes and will correct the typos, thanks for pointing them out. We have also decided to add to OWL 2 QL reflexive, irreflexive, & asymmetric property axioms. Moreover, we will fix the inaccuracies in the complexity table, following your suggestions and discussions with Maurizio: for data complexity, we will add that OWL 2 QL is in AC_0, i.e., queries are first order rewritable and that the taxonomic complexity is NLogSpace-complete. Finally, we have decided *not* to add sameAs to OWL 2 QL, but to add a paragraph that explains that, if one wants to handle ontologies that are OWL 2 QL plus sameAs, then one can use a preprocessing step that materializes the sameAs relation and uses it in query answering procedures to simulate individual equality reasoning (see http://www.w3.org/2007/OWL/wiki/Profiles#Feature_Overview_2).
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on behalf of the W3C OWL Working Group
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|We have two comments on OWL 2 QL, document 7:
1. In section 3.1 it's written that "the following constructs are not supported in OWL 2 QL:
- reflexive properties
- irreflexive properties
- asymmetric properties
- equality (sameIndividual)
In fact, as shown in  below, one can (easily) reduce (in LogSpace) query answering in OWL 2 QL extended with the above mentioned constructs to query answering in OWL 2 QL as defined in the document (that is, without those constructs). Thus, the data complexity remains in LogSpace, and so the constructs CAN BE INCLUDED in OWL 2 QL without changing complexity.
Furthermore, if we add
- transitive properties
then query answering becomes data complete in NLogSpace.
2. In Section 5, Table 10, it's written that taxonomic complexity and combined complexity of OWL 2 QL is in PTIME. In fact, it NLogSpace-complete, even with all the constructs mentioned above.
 A. Artale, D. Calvanese, R. Kontchakov, and M. Zakharyaschev, The DL-Lite family and relatives. Available at http://www.dcs.bbk.ac.uk/~michael/DL-LiteFamily.pdf