- From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
- Date: Wed, 24 Sep 2008 12:44:16 -0400 (EDT)
- To: alanruttenberg@gmail.com
- Cc: public-owl-wg@w3.org
This is not so bad, but it still suffers from the problem that a trivial program can be minimally conforming. 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 16:45:01 UTC