Re: Primer comments: editorial

On Donnerstag, 4. Juni 2009, Jim Hendler wrote:
> I think the primer is much improved, hope to get a chance for a real
> review later - here are some comments on the profiles section - I
> consider these all to be editorial, as none of them change anything
> technical in the design or the descriptions thereof:

Hi Jim, 

thanks a lot for your comments. I agree that these can be addressed as 
editorial changes -- below is my summary of the changes.

>
> ----
> OWL EL:
> The first paragraph says
>
> > OWL 2 EL makes a good approximation target, that is, by only a
> > little simplification one can get an OWL 2 EL ontology and preserve
> > much of the meaning of the original ontology.
>
> given that "good approximation target' is hard to understand, and is
> thus immediately explained, maybe this would make the strength of OWL
> 2 EL clearer if it dropped the subclause and read:
>
> "For many large, class-expression oriented ontologies, by only a
> little simplification one can get an OWL 2 EL ontology and preserve
> the bulk of the meaning of the original ontology."
>
> which I think more clearly empohasizes this strength of EL.

Wording improved as suggested.

>
> -----
>
> The primer says of OWL EL
>
> > Not only does it scale well for facts and axioms, but it scales well
> > for complex expressions.
>
> I think that second clause is too imprecise, because in profiles we
> say "OWL 2 EL places restrictions on the type of class restrictions
> that can be used in axioms."
>
> which would seem to be contradictory.  I suggest either removing the
> sentence above, or coming up with a more technically correct way of
> saying "complex expressions" to avoid sounding self-contradicting.

This part has already been modified since the last Primer WD, and the quoted 
text is no longer part of the section, see

http://www.w3.org/2007/OWL/wiki/Primer#OWL_2_EL

>
> -----
> OWL QL
>
> I thought this section was good, one nit:
>    it says "can be realized on top of standard relational database
> technology" - where "on top of" seems to me to be unclear - maybe
> "...can be realized using standard relational database technology"
> would be clearer?

Yes, I think so too. Changed.

>
> ----
> OWL RL
>
>
> contrast this from QL
>
> > Among other constructs, OWL 2 QL disallows existential
> > quantification of roles to a class expression, i.e. it can be stated
> > that every person has a parent but not that every person has a
> > female parent. Moreover property chain axioms are not supported.
>
> with this from the RL
>
> > One downside of OWL 2 RL is that it cannot express that the
> > existence of an individual enforces the existence of another
> > individual: for instance, the statement “every person has a parent”
> > is not expressible in OWL RL.
>
> Why are we calling this a "downside" for RL, but simply stating it as
> an aspect of the language for QL (and there is similar in EL) ?  I
> would suggest we reword the RL one to be more like the one in QL - i.e
>
> "Among other constructs, OWL 2 RL disallows statements where the
> existence of an individual enforces the existence of another
> individual: for instance, the statement “every person has a parent” is
> not expressible in OWL RL."

I agree. Changed.

>
> Also, in RL it says:
> > Suitable rule-based implementations of OWL 2 RL will have desirable
> > computational properties; for example, they can return all and only
> > the correct answers to certain kinds of queries. Such an
> > implementation can also be used with arbitrary RDF graphs. (In this
> > case, however, these properties no longer hold – in particular, it
> > is no longer possible to guarantee that all correct answers can be
> > returned.)
>
> which is correct, but I think confusing (just in the use of the
> English) - I'd suggest in this case the technical vocabulary might be
> more useful - how about:
>
> "Suitable rule-based implementations of OWL 2 RL will have desirable
> computational properties; for example, they are sound and complete
> with respect to many kinds of queries. OWL 2 RL can also be used with
> arbitrary RDF graphs., however in this case, as with OWL Full, there
> may be cases where completeness cannot be guaranteed. "

This section has already been changed to improve this wording since the last 
Primer WD. The current version is here:

http://www.w3.org/2007/OWL/wiki/Primer#OWL_2_RL

>
>
> Again, I think the section here is very useful, and consider these
> editorial suggestions that would not effect the LC status of the
> documents

I fully agree. The diff substantiates this: [1]

Markus

[1] 
http://www.w3.org/2007/OWL/wiki/index.php?title=Primer&diff=24447&oldid=24444


-- 
Markus Krötzsch
Institut AIFB, Universität Karlsruhe (TH), 76128 Karlsruhe
phone +49 (0)721 608 7362          fax +49 (0)721 608 5998
mak@aifb.uni-karlsruhe.de          www  http://korrekt.org