- From: Alan Ruttenberg <alanruttenberg@gmail.com>
- Date: Wed, 24 Sep 2008 12:51:47 -0400
- To: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
- Cc: public-owl-wg@w3.org
- Message-ID: <29af5e2d0809240951q1b3248bt64510720f99c9375@mail.gmail.com>
On Wed, Sep 24, 2008 at 12:44 PM, Peter F. Patel-Schneider < pfps@research.bell-labs.com> wrote: > This is not so bad, but it still suffers from the problem that a trivial > program can be minimally conforming. Yes. I'm not sure what to do about that, although it might not, in practice, be too bad as such a program would be laughed out of the room. I'm a little worried that the current OWL-RL statements suffers similarly. OTOH, I have thought in the past that the word "complete" ought to be spoken more when referring to implementations of reasoners/fragments that are - it's a positive word and brings what I think are the right connotations. -Alan > > > peter > > > From: "Alan Ruttenberg" <alanruttenberg@gmail.com> > Subject: Re: wording on Unknown returns in Conformance > Date: Wed, 24 Sep 2008 12:37:49 -0400 > > > I was thinking about something along the lines of (specific words could > > change). My changes in italics. There's probably a better word than > > "minimally > > conforming" but I can't think of one right now. > > > > An minimally conforming OWL 2 Full entailment checker is an OWL 2 > > entailment > > checker that takes RDF documents as input, and uses the RDF-Based > > Semantics > > [OWL 2 RDF-Based Semantics]. It must return True only when O1 entails > > O2, > > and it must return False only when O1 does not entail O2. It may return > > Unknown if it is not capable of determining whether an entailment holds > > or > > not. > > A complete OWL 2 Full entailment checker is a minimally conforming OWL 2 > > Full entailment checker that should not return unknown. > > > > Then, in section 2.2.1 > > > > It *must* provide a means to determine the semantics it uses (either the > > Model-Theoretic Semantics [OWL 2 > > Semantics<http://www.w3.org/2007/OWL/wiki/Test#ref-owl-2-semantics>] > > or the RDF-Based Semantics [OWL 2 RDF-Based > > Semantics<http://www.w3.org/2007/OWL/wiki/Test#ref-owl-2-rdf-semantics > >]), > > and whether it is minimally conformant or complete; for example, in its > > supporting documentation. > > > > Similarly for other profiles. > > > > I would add a note that at the time of publication it isn't known > > whether > > complete conformance for OWL Full is possible. > > > > -Alan > > > > On Wed, Sep 24, 2008 at 12:26 PM, Peter F. Patel-Schneider < > > pfps@research.bell-labs.com> wrote: > > > Huh? What is this, and how would it be done. > > > > > > peter > > > > > > From: "Alan Ruttenberg" <alanruttenberg@gmail.com> > > > Subject: Re: wording on Unknown returns in Conformance > > > Date: Wed, 24 Sep 2008 12:17:07 -0400 > > > > > >> I had thought that it might be worth distinguishing distinct levels > > of > > >> conformance - complete versus incomplete. Do you think that would be > > a > > >> good idea? It bothers me a bit that conformance as specified for OWL > > >> Full, as stated now, is not known to be possible. > > >> -Alan > > >> > > >> > > >> On Wed, Sep 24, 2008 at 10:04 AM, Peter F. Patel-Schneider > > >> <pfps@research.bell-labs.com> wrote: > > >> > > > >> > There have been some comments on the "should not" wording in the > > >> > conformance part of the Test and Conformance document. > > >> > > > >> > The current wording includes > > >> > > > >> > An OWL 2 Full entailment checker is an OWL 2 entailment checker > > that > > >> > takes RDF documents as input, and uses the RDF-Based Semantics [OWL > > 2 > > >> > RDF-Based Semantics]. It MUST return True only when O1 entails O2, > > and > > >> > it MUST return False only when O1 does not entail O2. It SHOULD NOT > > >> > return Unknown. > > >> > > > >> > Without the last sentence, a trivial checker, i.e., one that always > > >> > returned "Unknown" would be just as good an OWL 2 Full entailment > > >> > checker as one that tried hard. > > >> > > > >> > Even worse, if the last sentence was removed from > > >> > > > >> > An OWL 2 DL entailment checker is an OWL 2 entailment checker that > > >> > takes OWL 2 DL ontology documents as input, and uses the Model > > >> > Theoretic Semantics [OWL 2 Semantics]. It MUST return True only > > when > > >> > O1 entails O2, and it MUST return False only when O1 does not > > entail > > >> > O2. It SHOULD NOT return Unknown. > > >> > > > >> > then a trivial checker would be just as good as a complete reasoner > > for > > >> > OWL 2 DL. > > >> > > > >> > > > >> > I thus feel that there needs to be some wording in the conformance > > >> > document to show that trivial checkers, or unnecessarily incomplete > > >> > checkers, are not as good as ones that return "Unknown" in fewer > > cases. > > >> > > > >> > Remember that "should not" is not the same as "must not". A > > checker > > >> > could return "Unknown" if > > >> > 1/ it ran out of resources (memory, time, etc.); or > > >> > 2/ it is an incomplete reasoner (for OWL 2 Full, for example, or > > even > > >> > for OWL 2 DL). > > >> > The above reasons (or others) could be used by entailment checkers > > to > > >> > provide a justification for "Unknown" answers. I feel, however, > > that > > >> > this is outside the scope of the specification. > > >> > > > >> > Perhaps it would be useful to add some wording on justifying > > "Unknown" > > >> > to the document, but I think that most of this is implied by the > > use of > > >> > "should not". > > >> > > > >> > peter > > >> > > > >> > > > > >
Received on Wednesday, 24 September 2008 16:52:30 UTC