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Re: S&AS review: Section 5

From: Peter F. Patel-Schneider <pfps@research.bell-labs.com>
Date: Thu, 27 Mar 2003 10:26:32 -0500 (EST)
Message-Id: <20030327.102632.101061454.pfps@research.bell-labs.com>
To: herman.ter.horst@philips.com
Cc: www-webont-wg@w3.org

From: herman.ter.horst@philips.com
Subject: Re: S&AS review: Section 5
Date: Thu, 27 Mar 2003 15:11:19 +0100

> >> OWL - Semantics and Abstract Syntax
> >> Version of 20 March 2003
> >> 
> >> As in the other message, I go sequentially through the text.
> >> 
> >> 

[...]



> >> clearly defines the domain of ICEXT to be the set IC. 
> >> This should be incorporated in the document. 
> >> For your convenience, I completely describe the 
> >> required changes, also in connection with the appendix.
> >
> >> Replace the sentence
> >> >CEXTI is then defined as CEXTI(c) = ...
> >> by the following two sentences:
> >> "CI, the set of classes, is defined by
> >> CI = {x in RI | <x,SI(rdfs:Class)> is in EXTI(SI(rdf:type)>}.
> >> CEXTI is a mapping from CI to P(RI), defined for each
> >> c in CI by CEXTI(c) = [exactly what is already in the text].
> >> "
> >
> >I disagree with this characterisation of ICEXT, and will not make these
> >changes.
> >
> Here is the current version of the normative definition,
> which clearly states that the domain of ICEXT is IC,
> and in which the definition of IC and ICEXT is clearly 
> equivalent to what I wrote above:
> 
> RDFSemantics>An rdfs-interpretation of V is an rdf-interpretation 
> >I of (V union rdfV union rdfsV) with a distinguished subset IC 
> >of the universe and a mapping ICEXT from IC to the set of 
> >subsets of IR, which satisfies the following semantic 
> >conditions and all the triples in the subsequent table, 
> >called the RDFS axiomatic triples. 
> >[... I list only the first two conditions in the table:]
> >x is in ICEXT(y) iff <x,y> is in IEXT(I(rdf:type))
> >IC = ICEXT(I(rdfs:Class))
> 
> What the current version of S&AS does not yet incorporate
> is the domain requirement on ICEXT.
> There is no reason not to incorporate now in S&AS the correct 
> up-to-date definition of ICEXT.
> Your following two 'I disagree's apparently also derive 
> from this.

I'm going by the official version of the RDF semantics, not any private
editor's version.

> [...]
> 
> >
> >> The first table, "Conditions concerning the parts of the OWL
> >> universe and syntactic categories" needs to be completed
> >> in connection with CI:  Each of the 11 empty cells in the
> >> first column (SI(E) is in ...) needs to be filled with the
> >> set CI.  Otherwise, as discussed before, many invocations
> >> of CEXTI that occur later are are not clearly legal.
> >
> >I disagree.
> >
> >> I believe that five more lines need to be added to this table,
> >> for the following vocabulary elements
> >> (the reason is, as before, that otherwise it is not clear
> >> that various function invocations occurring later are legal):
> >> 
> >> If  E is                      .SI(E). .CEXTI(SI(E)).    and
> >>   owl:Datarange                 CI       ?      ? subsetof CI
> >>   owl:SymmetricProperty         CI       ?      ? subsetof IOP
> >>   owl:FunctionalProperty        CI       ?      ? subsetof IOP
> >>   owl:InverseFunctionalProperty CI       ?      ? subsetof IOP
> >>   owl:TransitiveProperty        CI       ?      ? subsetof IOP
> >> Where I put a question mark I leave it open whether you
> >> want to define specific sets for these; this would seem 
> >> most natural to me.
> >
> >I disagree.
> >
> >> There are only two further additions to be made:
> >> the entities SI(owl:DeprecatedClass) and SI(owl:DeprecatedClass)
> >> need to be put in CI as well.
> >> (This is used in the proofs in Appendix A.1.)
> >
> >Done.
> 
> Please point out where you have done this - I cannot find it.

What I've done is adequate for the official version of the RDF semantics.

[...]

> Herman

peter
Received on Thursday, 27 March 2003 10:26:49 GMT

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