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Re: firts and rdf:rest as functional property

From: Richard H. McCullough <rhm@pioneerca.com>
Date: Fri, 20 Mar 2009 07:37:57 -0700
Message-ID: <0A0A4686B2744DE7A21FCC3348AB7FA4@rhm8200>
To: "Bijan Parsia" <bparsia@cs.man.ac.uk>, Reto Bachmann-Gmür <reto.bachmann@trialox.org>
Cc: "Michael Schneider" <schneid@fzi.de>, "Semantic Web" <semantic-web@w3.org>
I have often wondered why RDF doesn't allow lists
to written in the style that is used in programming
languages today:


You can use "list" as a predicate

    X list [a,b,c,d]

They're easy to parse, easy to read.

Dick McCullough
Ayn Rand do speak od mKR done;
mKE do enhance od Real Intelligence done;
knowledge := man do identify od existent done;
knowledge haspart proposition list;

----- Original Message ----- 
From: "Bijan Parsia" <bparsia@cs.man.ac.uk>
To: "Reto Bachmann-Gmür" <reto.bachmann@trialox.org>
Cc: "Michael Schneider" <schneid@fzi.de>; "Semantic Web" 
Sent: Friday, March 20, 2009 7:14 AM
Subject: Re: firts and rdf:rest as functional property

> On 20 Mar 2009, at 14:02, Reto Bachmann-Gmür wrote:
>> Hi Bijan
>>> ...
>>>> If rdf:rest
>>>> and rdf:first are not functional a list could typically not be be
>>>> splitted into different rdf molecules[1]. Splitting graphs into  small
>>>> components is essential for applications like diff, sync[2] and
>>>> versioning[3].
>>> If you are doing to decompose *semantically*, then functionality will
>>> be too weak to do the job anyway.
>> Not sure if I understand you, if a do decomposition of a graph into  RDF
>> molecules[1] (as this is done in the Graph Versioning System GVS  [2]) if
>> the base ontology contains the fact that rdf:rest and rdf:firts are
>> owl:functionalProperty a list will typically (i.e. if some of the
>> objects of the rdf:first statements are grounded or if the first
>> rdf:List resource is grounded) be split into many small components  while
>> otherwise it is (assuming the rdf:List resources are anonymous) all
>> contained in one molecule. Isn't the decomposition into a semantical
>> decomposition?
> Sorry, don't have time to peek at that at the moment.
> By semantic decomposition, I mean that there will be certain  properties 
> preserved in the decomposition. See the slides for:
> http://owl.cs.manchester.ac.uk/2008/iswc-modtut/
> Functionality isn't necessarily the problem, but I presume you want  first 
> to be min1 as well (for a well formed list...having holes is as  bad as 
> having tentacles).
> Functionality might have the surprising effect of entailing that two 
> things are the same. Which might not be how you want to "repair" the 
> tentacled list.
> So, it's not clear to me that this is the right tool for the job.  Perhaps 
> I'm wrong about what job you're trying to do?
> rdf:Lists were not introduced for modeling, but for encoding the  syntax 
> of OWL (taken from DAML+OIL). They have been pressed into  service for 
> modeling, but the built-in semantics (IMHO) as well as  other aspects of 
> them aren't really suited for modeling. But we model  with what's at hand.
> Cheers,
> Bijan.
Received on Friday, 20 March 2009 14:39:59 UTC

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