RE: [LC response] To Jonathan Rees

Hello,

You are right -- I got mixed up. In UML, associations and elementary values are
instances of UML metaclasses; however, going there might be way too complicated
for the standard readers. Hence, I've followed your suggestion and have changed
the sentence to this:

    Objects ''o<sub>1</sub>'' and ''o<sub>2</sub>'' from the structural
    specification are ''structurally equivalent'' if the following conditions
    hold:

Please let us know whether this addresses your concerns. Thanks again for this
valuable input!

Regards,

	Boris


> -----Original Message-----
> From: public-owl-comments-request@w3.org [mailto:public-owl-comments-
> request@w3.org] On Behalf Of Jonathan Rees
> Sent: 30 March 2009 15:42
> To: Ian Horrocks
> Cc: public-owl-comments@w3.org
> Subject: Re: [LC response] To Jonathan Rees
> 
> On Mar 27, 2009, at 2:50 PM, Ian Horrocks wrote:
> 
> > Dear Jonathan
> >
> > We sent you a response [1] to your comment [2] on the OWL 2 Web
> > Ontology Language last call drafts, but to date we do not appear to
> > have received any reply. If we don't hear from you we will assume
> > that you are satisfied with the working group's response to your
> > comment.
> >
> > Regards,
> > Ian Horrocks
> > on behalf of the W3C OWL Working Group
> >
> > [1] http://lists.w3.org/Archives/Public/public-owl-
> comments/2009Mar/0044.html
> > [2]
> http://www.w3.org/mid/760bcb2a0901251002p3e1be898s246b23e4284ac49a@mail.gmail.
> com
> 
> The definition of structural equivalence doesn't make sense. Here is
> what's in the wiki now:
> 
> <snip>
> Instances o1 and o2 of the UML classes from the structural
> specification are structurally equivalent if the following conditions
> hold:
> 
>      * If o1 and o2 are atomic values, such as strings or integers,
> they are structurally equivalent if they are equal according to the
> notion of equality of the respective UML type.
>      * If o1 and o2 are unordered associations without repetitions,
> they are structurally equivalent if each element of o1 is structurally
> equivalent to some element of o2 and vice versa.
>      * If o1 and o2 are ordered associations with repetitions, they
> are structurally equivalent if they contain the same number of
> elements and each element of o1 is structurally equivalent to the
> element of o2 with the same index.
>      * If o1 and o2 are instances of UML classes from the structural
> specification, they are structurally equivalent if
>            o both o1 and o2 are instances of the same UML class, and
>            o each association of o1 is structurally equivalent to the
> corresponding association of o2 and vice versa.
> </snip>
> 
> By hypothesis, o1 and o2 are instances of UML classes. Therefore, by
> the first three points, atomic values, unordered associations, and
> ordered associations are all also instances of UML classes. As I do
> not know the details of UML I might assume that this is OK. However,
> the last bullet point repeats the hypothesis that o1 and o2 are
> instances of UML classes from the S.S. This does not sound right to
> me, and suggests a possible editorial improvement, if not an error.
> 
> I suggest rewriting to either remove the first hypothesis (at the very
> top) somehow, if atomic values and so on are not instances of UML
> classes, or the antecedent of the fourth bullet point, if they are.
> 
> Jonathan
>

Received on Monday, 30 March 2009 16:00:34 UTC