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Re: What is it that's wrong with rdf:List

From: Pat Hayes <phayes@ihmc.us>
Date: Thu, 17 Jun 2010 21:44:35 -0500
Cc: Semantic Web <semantic-web@w3.org>
Message-Id: <3C64FC92-B11A-43DF-99DC-B3A03DF7E842@ihmc.us>
To: Norman Gray <norman@astro.gla.ac.uk>

On Jun 17, 2010, at 5:19 PM, Norman Gray wrote:

>
> Greetings.
>
> What is it that's so wrong/bad/wicked with rdf:List?  Can anyone  
> point me to some reading?
>
> I have the impression that 'everyone knows that' rdf:List is bad in  
> some way, but can't find any explicit account of what's so very  
> wrong with it.  This is a pity, because I find myself wanting to use  
> it.
>
> The page at [1] implies in passing that rdf:List represents 'bad  
> modelling practice'.  [2] is an (unanswered) list question about  
> rdf:List making an ontology OWL Full (which is clearly awkward if  
> you want to do reasoning with things, but less so if you simply want  
> to express things).  [3] suggests ... well, I'm not completely clear  
> what it suggests, but it seems that rdf:List isn't favourite for  
> expressing lists.
>

OK, heres the issue. Note that both [1] and [2] are written from the  
point of view of writing OWL, not RDF in isolation. There is  
absolutely nothing wrong with rdf:List if all you want to do is use  
RDF or RDFS. But OWL chose to use rdf:LIst itself as its normative way  
of encoding OWL syntax into RDF graphs. So if you are using OWL,  
following the OWL-DL rules, then suddenly the rdf:List namespace has  
become restricted vocabulary, as it is part of the OWL syntax itself.  
OWL-DL also puts things like rdf:type into that restricted category,  
by the way, because it also regards these as part of it's restricted  
syntax. They aren't illegal, but you have to treat them differently  
from "user-defined" classes and properties. So to be safe, the safest  
way to treat all these when using OWL-DL is to not use them at all.  
None of this applies to OWL-Full, because OWL-Full deliberately  
refuses to disbar anything, its got a no-holds-barred approach to  
syntax.

> And what's the alternative, if I want to say in RDF that a  
> particular thing is related to an ordered set of other things --  
> perhaps an article has a particular sequence of authors?  [4] refers  
> to an OWLList ontology (and a broken link to a rationale).  I follow  
> how that ontology works, but don't get the significance of the  
> apparently minor ways in which it's different from rdf:List.

Its only different by being a different namespace, so its not going to  
get confused with OWL syntax by an OWL-RDF parser.

Pat Hayes

>
> Thanks for any pointers.  Best wishes,
>
> Norman
>
>
> [1] http://www.w3.org/2007/OWL/wiki/RDF_list_vocabulary
> [2] http://osdir.com/ml/misc.ontology.protege.owl/2004-04/ 
> msg00761.html
> [3] http://oxfordrepo.blogspot.com/2009/02/pushing-bagit-manifest-concept-little.html
> [4] http://www.co-ode.org/ontologies/lists/2008/09/11/
>
> -- 
> Norman Gray  :  http://nxg.me.uk
>
>
>

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Received on Friday, 18 June 2010 02:45:38 GMT

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