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Re: pfps-22,pfps-23: "reserved names in abstract syntax", pushback

From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
Date: Tue, 01 Jul 2003 18:18:50 +0100
Message-ID: <3F01C27A.5000507@hplb.hpl.hp.com>
To: Graham Klyne <gk@ninebynine.org>
CC: w3c-rdfcore-wg@w3.org



I would be happy to go forward with this as a listed objection.

I think Peter has adequately understood our intent, he sees some black, 
some white and a grey area.

rdfs:Class rdfs:Class rdfs:Class .

is not encouraged, nor is it absolutely prohibited.
The intent is that any usage by OWL is explicitly blessed.
We perhaps should ask Peter if we have forgotten one.

I suggest we say:

"The RDF Core WG is committed to supporting the needs of OWL.
We believe that the intent of what semantic extensions may do
  is clarified by having such a thorough example as the OWL Semantics being 
published concurrently."

in a response to peter, but decline to make further changes.



Jeremy


Graham Klyne wrote:

> 
> 
>> From: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
>>
>> I am still unhappy with the way that RDF sort of reserves certain 
>> things to
>> itself, but also sort of allows anyone to do anything.
> 
> 
> We've been asked [2] to be clearer about RDF namespace terms (full 
> message below).
> 
> I'll try and pick out some key points for discussion.
> 
> 
> 1. "syntactic" URIs.
> 
> I think we could be stronger about these and say that they MUST NOT 
> appear in an RDF abstract syntax graph.  (Does the syntax document 
> already say this?)  Concepts (section 4) currently says that they 
> "should not be used in RDF to denote any kind of resource" -- which 
> might be strengthened to "must not".
> 
> 
> 2.  Status of rdfs:Class rdfs:Class rdfs:Class .
> 
> My view is that this is syntactically legitimate RDF, whose truth is 
> neither asserted nor denied by the RDF specification.  Use of statements 
> like this in RDF data is strongly discouraged, except as part of a 
> semantic extension in conformance with the General Monotonicity Lemma [1].
> 
> Some extra words to this effect might be added to Concepts section 2.2.6:
>   
> http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-concepts-20030117/#section-anyone 
> 
> 
> e.g.
> 
> [[
> While legal RDF data may make assertions about concepts that are 
> introduced by the RDF specification (the values, classes and properties 
> indicated by specific RDF vocabulary terms), such use is strongly 
> discouraged and may lead to RDF data that is useless when processed in 
> accordance with normal RDF entailments.  As noted in the RDF formal 
> semantics [RDF-SEMANTICS], semantic extensions may further constrain the 
> meaning of RDF vocabulary terms in ways that conform to the General 
> Monotonicity Lemma.
> ]]
> 
> Also, the paragraph in section 4 that currently reads:
> [[
> Vocabulary terms in the rdf: namespace are listed in section 5.1 of the 
> RDF syntax specification [RDF-SYNTAX].  Some of these terms are defined 
> by the RDF specifications to denote specific concepts.  Others have 
> purely syntactic purpose (e.g. rdf:ID is part of the RDF/XML syntax) and 
> should not be used in RDF to denote any kind of resource.
> ]]
> 
> could add something like:
> 
> [[
> The meaning of non-syntactic RDF vocabulary terms is defined by the RDF 
> Semantics specification [RDF-SEMANTICS].
> ]]
> 
> 
> 3.  what is the status of OWL's use of the RDF and RDFS vocabularies?
> 
> I regard these as fine as long as they conform with the General 
> Monotonicity Lemma [1].  I can't easily tell, but I assume they do   I 
> think this is covered above.
> 
> #g
> -- 
> 
> [1] http://www.ihmc.us/users/phayes/RDF_Semant_Edit_Weak.html#MonSemExt
> 
> [2] 
> http://lists.w3.org/Archives/Public/www-rdf-comments/2003JulSep/0006.html
>     (message content below)
> 
> 
>> Cc: www-rdf-comments@w3.org
>> Subject: Re: [closed] pfps-22,pfps-23: "reserved names in abstract 
>> syntax"
>> From: "Peter F. Patel-Schneider" <pfps@research.bell-labs.com>
>>
>> I am still unhappy with the way that RDF sort of reserves certain 
>> things to
>> itself, but also sort of allows anyone to do anything.
>>
>> In particular, Section 2.2.6 says ``RDF is an open-world framework that
>> allows anyone to make statements about any resource'' but Section 4 says
>> ``Certain URI references are reserved for use by RDF and should not be 
>> used
>> in ways not supported by the RDF specficiations.''
>>
>> So, what is the status of, for example,
>>
>>         rdfs:Class rdfs:Class rdfs:Class .
>>
>> Is it a) completely unobjectionable, b) something that should not be 
>> done,
>> or c) forbidden?  Section 2.2.6 argues for a); Section 4 argues for b) or
>> maybe even c).
>>
>> Similarly, what is the status of OWL's use of the RDF and RDFS
>> vocabularies?  (See
>> http://www-db.research.bell-labs.com/user/pfps/owl/semantics/rdfs.html#5.2 
>>
>> for the current editor's draft of the most relevant portion of the OWL
>> specifications.)  Is this something that any formal specification can
>> unobjectionably do, or is there something wrong with using the RDF and 
>> RDFS
>> vocabularies in this fashion?
>>
>> The RDF Semantics document makes this even less clear as it explicitly
>> mentions that semantic extensions may modify the meaning of 
>> rdfs:domain and
>> rdfs:range (Section 4.1), but does not say anthing similar for most other
>> elements of the RDF and RDFS vocabularies.
>>
>> peter
>>
>>
>>
>> From: Graham Klyne <gk@ninebynine.org>
>> Subject: [closed] pfps-22,pfps-23: "reserved names in abstract syntax"
>> Date: Tue, 01 Jul 2003 10:26:19 +0100
>>
>> > Peter,
>> >
>> > With reference to your comments raised in:
>> > 
>> http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0148.html
>> > and subsequent exchanges linked from:
>> > 
>> http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0314.html
>> > specifically with reference to the issue of reserved names in the RDF
>> > syntax, and the notion of uses "sanctioned by" RDF, which were 
>> crystalized in:
>> > 
>> http://lists.w3.org/Archives/Public/www-rdf-comments/2003JanMar/0194.html
>> >
>> > The RDFcore working group has resolved per:
>> >    http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Apr/0207.html
>> > (agendum 16) to revise the text along the lines of:
>> >    http://lists.w3.org/Archives/Public/w3c-rdfcore-wg/2003Apr/0201.html
>> >
>> > Revised text can be previewed in the editors' working draft at:
>> >    http://www.w3.org/2001/sw/RDFCore/TR/WD-rdf-concepts-20030117
>> >
>> > Could you please respond, copying www-rdf-comments@w3.org, indicating
>> > whether or not you regard your comments have been adequately addressed.
>> >
>> > Thank you for your attention,
>> >
>> > Graham Klyne
>> > (for RDFcore working group)
>> >
>> > #g
>> >
>> >
>> > -------------------
>> > Graham Klyne
>> > <GK@NineByNine.org>
>> > PGP: 0FAA 69FF C083 000B A2E9  A131 01B9 1C7A DBCA CB5E
> 
> 
> -------------------
> Graham Klyne
> <GK@NineByNine.org>
> PGP: 0FAA 69FF C083 000B A2E9  A131 01B9 1C7A DBCA CB5E
> 
Received on Tuesday, 1 July 2003 13:21:19 EDT

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