- From: Carsten Lutz <clu@tcs.inf.tu-dresden.de>
- Date: Thu, 29 Nov 2007 08:30:19 +0100 (CET)
- To: Bernardo Cuenca Grau <bcg@cs.man.ac.uk>
- Cc: OWL Working Group WG <public-owl-wg@w3.org>
On Thu, 29 Nov 2007, Bernardo Cuenca Grau wrote: > >>> I have a question, however, concerning the interaction between range >>> restrictions and role inclusion axioms. Note that the EL++ version in the >>> fragments document does impose some restrictions in the use of (complex) role >>> inclusion axioms, namely the same ones as SROIQ imposes. >> >> The document is a bit confusing in that respect stating that "The >> language EL++, as presented here, is not a fragment of OWL DL, since >> it provides complex inclusion axioms on Object Properties." > > Well, here I meant that EL++ is not contained in OWL DL, because SHOIN > does not allow for complex inclusion axioms. > >> , but also >> "in particular, this document enforces the regularity condition on >> complex property inclusion axioms required in OWL 1.1. With this >> restriction, EL++ is a fragment of OWL 1.1." > > What I meant is that the EL++ Tractable Fragments document imposes the > same regularity condition on the role inclusion axioms as OWL 1.1. > Therefore, the version of EL++ in this document is not strictly the same > as the one in your IJCAI-05 paper, which didn't impose regularity > conditions. Also, I included range restrictions because I thought they > were harmless, but now I see this has to be checked out. In short, if you > can check that the role inclusion axioms and the range restrictions do not > interact badly under regularity conditions, then the document is all > right. I agree that these statements should be made clearer. I agree with everything you say. greetings, Carsten > Bernardo > >> >>> My question is >>> whether these restrictions are not sufficient. If they do not suffice, I >>> agree with Carsten in that identifying a variant of EL++ that allows for >>> domain and range and imposes reasonable constraints in the use of role >>> inclusion axioms would be a good thing to have and that version should be >>> the one included in the document. >> >> I suppose that they are sufficient, but I never checked the details. >> Actually, these restrictions were precisely what I meant in my last >> mail when talking of a new variant. So there is actually no disagreement >> here, only somebody has to verify that things remain tractable. I'll >> try to do that until the Manchester F2F. >> >>> I think that the issue whether this fragment which should be called ``OWL >>> Light" is a much more controversial one. In principle I think there should be >>> no single ``OWL Light'', but a reasonable menu of choices for such an OWL >>> Light that each particular user could pick depending on his application >>> needs. >> >> I disagree for the reasons given in my mail(s). Anyway, we should maybe >> not mix these two issues. >> >> greetings, >> Carsten >> >> -- >> * Carsten Lutz, Institut f"ur Theoretische Informatik, TU Dresden * >> * Office phone:++49 351 46339171 mailto:lutz@tcs.inf.tu-dresden.de * >> > > > *********************************** > Dr. Bernardo Cuenca Grau > Research Fellow > Information Management Group > School Of Computer Science > University of Manchester, UK > http://www.cs.man.ac.uk/~bcg > ************************************ > > > -- * Carsten Lutz, Institut f"ur Theoretische Informatik, TU Dresden * * Office phone:++49 351 46339171 mailto:lutz@tcs.inf.tu-dresden.de *
Received on Thursday, 29 November 2007 07:30:41 UTC