- From: Jeremy Carroll <jjc@hplb.hpl.hp.com>
- Date: Tue, 01 Jul 2003 18:18:50 +0100
- 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 UTC