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Re: pfps-12 lists are not well formed

From: Karsten Tolle <tolle@dbis.informatik.uni-frankfurt.de>
Date: Fri, 20 Jun 2003 11:48:39 +0200
Message-ID: <004a01c33711$3ef681a0$230b028d@HANNOVER>
To: <danbri@w3.org>, "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
Cc: <bwm@hplb.hpl.hp.com>, <www-rdf-comments@w3.org>

Dear all,

I agree with Peter, it goes in the right direction.

The text you want to enter looks good. It should be remarked
(probably already can be found in the context) that the applications need
to deside what to do in the different cases (only one rdf:first, many
rdf:first or
none rdf:first).

Karsten

P.S.: But, at the end for me the main problem having collections and lists
in parallel
remains.
___________________________________
Karsten Tolle
----- Original Message -----
From: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
To: <danbri@w3.org>
Cc: <tolle@dbis.informatik.uni-frankfurt.de>; <bwm@hplb.hpl.hp.com>;
<www-rdf-comments@w3.org>
Sent: Wednesday, June 18, 2003 10:04 PM
Subject: Re: pfps-12 lists are not well formed


> This appears to be on the right track, but I have no way of viewing the
> other changes, and no way of viewing the changes in context, so I don't
see
> how I can determine whether the changes are satisfactory.
>
> Peter F. Patel-Schneider
> Bell Labs Research
> Lucent Technologies
>
>
>
> From: Dan Brickley <danbri@w3.org>
> Subject: Re: pfps-12 lists are not well formed
> Date: Wed, 18 Jun 2003 12:28:27 -0400
>
> > resent copying Karsten, who also raised this issue. Karsten, could you
> > respond per the request below, letting us know if this is a satisfactory
> > resolution of your concern?
> >
> > Thanks again for your comments on our work,
> >
> > Dan
> >
> > previous discussion:
> >
http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0422.html
> >
> > * Dan Brickley <danbri@w3.org> [2003-06-18 12:16-0400]
> > >
> > > * Peter F. Patel-Schneider <pfps@research.bell-labs.com> [2003-05-25
07:24-0400]
> > > >
> > > > From: Brian McBride <bwm@hplb.hpl.hp.com>
> > > > Subject: pfps-12 lists are not well formed
> > > > Date: Sat, 24 May 2003 13:58:39 +0100
> > > >
> > > > > Peter,
> > > > >
> > > > > Danbri and I have been discussing how to resolve your issue about
the
> > > > > wellformedness of lists:
> > > > >
> > > > >    http://www.w3.org/2001/sw/RDFCore/20030123-issues/#pfps-12
> > > > >
> > > > > We are proposing to add the following note to the text at:
> > > > >
> > > > >    http://www.w3.org/TR/rdf-schema/#ch_collectionvocab
> > > > >
> > > > > as the last paragraph.
> > > > >
> > > > > [[
> > > > > NOTE:  It is possible to construct RDF graphs that use the RDF
collections
> > > > > vocabulary to partially describe a list.  Similarly there are
graphs that
> > > > > use this vocabulary in a way that is consistent with the RDF(S)
formal
> > > > > semantics, yet do not represent "well formed" lists.
> > > > > ]]
> > > > >
> > > > > We considered trying to trying to provide a full prose account of
the
> > > > > wellformedness of lists, but are currently disinclined to attempt
such an
> > > > > intricate task in natural language.
> > > > >
> > > > > Will adding this note address your concern.  If not, could you
please
> > > > > suggest alternative text that you would find more satisfactory.
> > > > >
> > > > > Brian
> > > >
> > > > I fail to see how this response addresses my comment.
> > > >
> > > > I don't see how it addresses
> > > >
> > > > > The RDF Schema document provides intended meanings for some of the
RDFS
> > > > > vocabulary that is not supported by the RDF Semantics.  Vocabulary
that
> > > > > fits into this category includes rdfs:label and rdfs:comment.
> > > > [from
http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0126.html]
> > > >
> > > > I don't see how it addresses
> > > >
> > > > > Consider the following three examples (slightly reformatted but
otherwise
> > > > > unchanged):
> > > > >
> > > > > rdf:type is an instance of rdf:Property that is used to state that
> > > > > a resource is an instance of a class.  A triple of the form:
> > > > > R rdf:type C
> > > > > states that C is an instance of rdfs:Class and R is an instance of
C.
> > > > >
> > > > > rdf:first is an instance of rdf:Property that is used to indicate
> > > > > the first item of a list.  A triple of the form:
> > > > > L rdf:first O
> > > > > states that L is an instance of rdf:List and that O is the first
> > > > > item of the list.
> > > > >
> > > > > rdfs:label is an instance of rdf:Property that is used to provide
a
> > > > > human-readable version of a resource's name.  A triple of the
form:
> > > > > R rdfs:label L
> > > > > states that L is a human readable label for R.
> > > > >
> > > > > There is essentially no difference between the way these three are
worded.
> > > > > However, the first (rdf:type) is a fundamental part of the
semantics of
> > > > > RDF.  There are semantic conditions in RDF that make the
description above
> > > > > for rdf:type part of the very meaning of RDF.  The second
(rdf:first) and
> > > > > third (rdfs:label), on the other hand, have a very different
status.  There
> > > > > are no semantic conditions that force the descriptions above for
these two
> > > > > vocabulary elements to play the roles given for them.
> > > > [from
http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0133.html]
> > > >
> > > > The point of my comments here has always been that there are parts
of the
> > > > RDF Schema document that go beyond what is supported by the RDF
semantics.
> > > > I believe that these parts of the document should be changed, and
that
> > > > changes to other parts of the document will not suffice to override
these
> > > > over-reaching parts of the document.
> > > >
> > > > For the case of rdf:first above, I would much prefer
> > > >
> > > >  rdf:first is an instance of rdf:Property that can be used to build
> > > >  descriptions of lists and other list-like structures.  A triple of
> > > >  the form:
> > > >  L rdf:first O
> > > >  states that there is a first-element relationship between L and O.
> > > >
> > > > Note:  RDFS does not require that there be only one first element
> > > > of a list-like structure, or even that a list-like structure have a
> > > > first element.
> > >
> > > This looks good. At the June 6th telecon[1] we decided to run with
your
> > > proposed form of words, but note that your text didn't mention the
> > > domain and range constraints associated with these concepts.
> > >
> > > A slightly amended form is:
> > > [[
> > > rdf:first is an instance of rdf:Property that can be used to
> > > build descriptions of lists and other list-like structures.
> > > A triple of the form:
> > >
> > >   L rdf:first O
> > >
> > > states that there is a first-element relationship between L and O.
> > > The rdfs:domain of rdf:first is rdf:List.  The rdfs:range of rdf:first
> > > is rdfs:Resource.
> > >
> > > Note:  RDFS does not require that there be only one first element of
> > > a list-like structure, or even that a list-like structure have a first
> > > element.
> > > ]]
> > >
> > >
> > > > I note that similar changes would have to be make for at least
rdf:rest and
> > > > rdf:List.
> > >
> > > Agreed.
> > >
> > > The WG (per [1]) proposes to close this issue by resolving to adopt
text in the
> > > above form for the RDF lists vocabulary.
> > >
> > > Please reply to this message as to whether this response is
> > > satisfactory, copying www-rdf-comments@w3.org.
> > >
> > > Dan
> > >
> > > [1]
http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Jun/0067.html
>
Received on Friday, 20 June 2003 05:48:32 GMT

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