- From: Boris Motik <boris.motik@comlab.ox.ac.uk>
- Date: Mon, 8 Sep 2008 08:55:36 +0100
- To: "'Thomas Schneider'" <schneidt@cs.man.ac.uk>
- Cc: <public-owl-wg@w3.org>
Hello, > -----Original Message----- > From: Thomas Schneider [mailto:schneidt@cs.man.ac.uk] > Sent: 07 September 2008 13:42 > To: Boris Motik > Cc: public-owl-wg@w3.org > Subject: Re: Review OWL 2 MT Semantics Document > > Hi Boris, > > thanks very much for your response and the changes you've made. I > agree with most of them, but have comments about the following ones: > > >> * 2.1 Vocabulary > >> > >> - Definition of N_{DT}: This is inconsistent with the OWL 2 > >> Specification: in Section 4 > >> [ http://www.w3.org/2007/OWL/wiki/Syntax#Datatype_Maps ] , it says > >> that N_DT *must not* contain rdfs:Literal. > >> > > > > All sets in the definition of the vocabulary are now called V_*. > > Thus, we now have N_DT in the datatype map and V_DT in the > > vocabulary. I hope things are now clearer. > > I think it's a good idea to change the N_* to V_*. However, now the > vocabulary V *over D* is not related to D any more: the enumeration of > the V_* should at least contain the statements V_{DT} = N_{DT}, V_{LT} > = N_{LT}, and V_{FA} = N_{FA}, shouldn't it? > That was already there; for example, the text said V_LT is the set of all literals of D. Nevertheless, I added an explicit equality to make things clear. > >> * 2.2 Interpretations > >> > >> - Definition of Delta_D: The notion (DT)^{DT} is very > >> confusing. Please don't use 'DT' for different things (datatype > >> and superscript of the interpretation function). One of these can > >> be replaced, e.g., by the lower case symbol 'dt'. The same for > >> ''OP'', ''DP'', ... -- and, of course, in the Syntax document. > >> > > [snip] I appreciate this concern; however, I simply don't see a nice solution to this. [snip] > OK, I find it clearer now. However, I now have the same problem as > Michael: my Firefox 3 shows the "alpha" as an italicised "a", while > Firefox 2 showed a clear "alpha". How about turning the "alpha" into > an "x" here? > Agreed -- I've changed it to "x". [snip] > Thanks, but I'm not 100% satisfied with the new heading "Keys": > Strictly speaking, "KeyFor(PE_1, ..., PE_n, CE)" is a key > *constraint*. A key is an n-tuple of individuals filling the > properties PE_1, ..., PE_n. Being picky, I'd rather like to see the > heading "Key Constraints" here ... > I'd prefer avoiding the term "constraint", as it might be confused with "integrity constraints". The difference between integrity constraints and axioms is something that is confusing OWL users quite a bit in general. Furthermore, I'm not sure why this type of axioms should be called a constraint while other axioms should not: all of them are just first-order sentences. > >> [Semantics of key constraints] > > > > In private communication Peter has suggested an even shorter way of > > writing this condition. > > Good, much clearer! I just feel that it should be made clearer that > the antecedent of the "imply" is everything behind the colon. I know > that this property doesn't make sense otherwise, but an extra pair of > brackets or so might help the reader to grasp the structure of this > non-trivial statement. > I'd prefer not introducing brackets because this statement is meant to be read as a natural-language statement. I appreciate your concerns, though, so I've reformatted and rephrased the condition a bit to make your point clearer (I hope). [snip] > >> - Proof, third-last sentence ("Clearly, ComplementOf(DT)^DT subset > >> ComplementOf(DT)DT'"): The map .^DT' hasn't ben defined because > >> Int' uses .^DT. Furthermore, why is it enough to consider only > >> data range expressions of the form ComplementOf(DT) and not > >> ComplementOf(DR) for arbitrary DR, or DatatypeRestriction(DT, > >> ...)? > >> > > > > D' should use .^{DT'}; this was a typo. > > Well, this was my mistake: I overlooked the fact that .^{DT'} was > given in D'. Now there's Michael's comment that .^{C'} isn't defined. > Oh, yes, sorry! [snip] Thanks again, and let me know should you have further comments. Regards, Boris
Received on Monday, 8 September 2008 07:57:15 UTC