W3C home > Mailing lists > Public > public-owl-wg@w3.org > November 2007

Re: ISSUE-2 (allDisjoint-RDF): No syntax for AllDisjoint in RDF mapping

From: Jim Hendler <hendler@cs.rpi.edu>
Date: Mon, 12 Nov 2007 21:25:19 -0500
Message-Id: <219CE1F9-864E-40A1-A60D-E71B338157C3@cs.rpi.edu>
Cc: "'Jeremy Carroll'" <jjc@hpl.hp.com>, <public-owl-wg@w3.org>
To: Boris Motik <boris.motik@comlab.ox.ac.uk>

I've never understood why roundtripping would be positive, some day  
someone will explain this to me (since the original document is still  
on the Web and has a URI, I can always find it, so why do I need to  
reproduce it) ... but thst's not my point

The real point is that if you have a list of N classes that are  
disjoint, you need N^^2 disjoint statements -- I gave an example  
where one could need thousands of disjoint statements -- here's the  
important use case from that mail:
I had pretty much decided the above was correct, but yesterday I was
talking to scientists about Semantic Web, and the following use case
came up -- they want to be able to take biological taxonoma and
represent in OWL, but they care very much what is and isn't disjoint
(class wise).  In particular, they want to be able to have it be the
case that at each level of the taxonomy the subclasses are disjoint
-- i.e. they want to be able to say

AllDisjoint (Animal, plant, ...) 1s of classes

AllDisjoint (Mammalian, reptilian, amhibian ...)   (10s of classes)

and then
AllDisjoint (canine, feline, ovine, cervine, ceatacean ...) (100s of  

but not to assert that within canines there is disjointness between
wolfes, dogs (of various types) etc, since these can interbreed etc.
They said the bottom level would be in the 100s of classes, so could
need 10000+ separate disjoint statements!

(Note that they used the animal example so I could understand, but
they were actually talking about more subtle distinctions in
proteomics and the like).
I am now on the advisory board of the EOL project where exactly this  
issue has come up again --- so since I'm not chair and am allowed to  
push an opinion - I think we MUST include a construct to avoid having  
to make the N^^2 statements in the RDF/XML documents (Which remain  
the normative exchange syntax for OWL)

[1] http://lists.w3.org/Archives/Public/www-webont-wg/2003May/0206.html

On Nov 12, 2007, at 9:07 PM, Boris Motik wrote:

> Hello,
> I don't think this is just a translation blowup problem; rather, it  
> is also about roundtripping from the structural spec to OWL/RDF
> and back. Ideally, roundtripping is quite desirable: note that the  
> structural spec is something that most APIs will use. It would be
> good if you can load an ontology, process it, save it, and be sure  
> that nothing has changed due to the drawbacks of one of the
> syntactic formats.
> Thus, I advocate keeping the language symmetric. Also, what is  
> really against making it so? A couple of new RDF built-in properties
> won't harm anyone.
> Boris
>> -----Original Message-----
>> From: public-owl-wg-request@w3.org [mailto:public-owl-wg- 
>> request@w3.org] On Behalf Of Jeremy Carroll
>> Sent: 12 November 2007 21:19
>> To: public-owl-wg@w3.org
>> Subject: Re: ISSUE-2 (allDisjoint-RDF): No syntax for AllDisjoint  
>> in RDF mapping
>> Summary: argue against new RDF/XML constructs for equivalent-classes,
>> equivalent-properties or equal-individuals, onb basis that all of  
>> these
>> have O(n) constructs already.
>> On Wed
>> Boris wrote:
>> [[
>> There are other n-ary constructs in the functional spec that are  
>> mapped
>> into binary constructs in the RDF: equivalences on classes,
>> disjointness and equivalences on properties, and sameAs and  
>> disjointFrom
>> on individuals.
>> It might make sense to broaden the discussion to these features as  
>> well.
>> ]]
>> The WebOnt rule for OWL 1.0 made sense to me:
>> For an n-ary construct in the abstract syntax, it must be possible to
>> have an O(n) construct with the same meaning.
>> For the disjoint classes we were hence suggesting that the ontology
>> writer should use the distinguished property approach.
>> This is documented in
>> http://www.w3.org/2001/sw/WebOnt/webont-issues.html#I5.21-drop- 
>> disjointUnionOf
>> linking to
>> http://www.w3.org/TR/owl-guide/#DisjointClasses
>> and linking to
>> http://www.w3.org/TR/2004/REC-owl-test-20040210/byIssue#I5.21-002
>> (which, in the Manifest file, is credited to Horrocks)
>> At the telecon we were told that there had proved to be operational
>> difficulties with this, hence a directed O(n) construct should be
>> supplied for RDF/XML.
>> For the positive constructs (equivalent class, same individual ...)
>> there are trivial O(n) RDF/XML constructs, so that we don't need to,
>> (and shouldn't?) provide alternative constructs.
>> i.e. to work through Boris's list:
>> [[
>> equivalences on classes,
>> equivalences on properties
>> sameAs on individuals
>>      trivially O(n)
>> disjointness on properties
>>      new, should be considered
>> disjointFrom
>>     on individuals ??? what's this.
>> ]]
>> Jeremy
Received on Tuesday, 13 November 2007 02:28:23 UTC

This archive was generated by hypermail 2.3.1 : Tuesday, 6 January 2015 21:42:00 UTC