Re: Issue-114

Hi Alan, Michael,

On 30 jun 2008, at 19:59, Alan Ruttenberg wrote:
> After discussion with Michael, we agreed to narrow this issue as  
> follows: We propose that the only punning in OWL is against  
> individuals - that is, anything named in OWL can have an individual  
> with the same (punned name).

Could you please clarify what the underlying reason is for this  
restriction? Object/datatype property punning and class/datatype  
punning were problems because of a compatibility issue with OWL Full.  
Is there a similar problem with class/property and individual/property  
punning?

If the restriction is based on an apparent lack of use cases I'm sure  
with a little effort we could come up with several. For instance,

1) The use of elephant and mouse properties to represent 'all  
elephants are bigger than all mice' (Markus' paper). The trick is to  
bridge the gap between TBox and RBox by making e.g. the class  
'elephant' equivalent to a self restriction on the 'elephant'  
property. Role inclusion axioms can then be used (together with the  
universal role) to connect all elephants to all mice. I feel that this  
is a case where class/property punning is appropriate.

2) A well known case is the relational nature of several roles, such  
as 'father'. Sometimes 'father' is used in the sense of 'has_father',  
sometimes it should be the class of fathers (or, more precisely, the  
role played by persons who are fathers). Again, using role inclusion  
axioms you can do a reification-like trick to infer the 'father'  
relation between two classes, given the chain has_father o played_by - 
 > father.

> This corresponds to what I believe is the commonly requested case,  
> and simplifies the current situation in which we have narrow  
> restrictions on certain forms of punning - no object/data property  
> punning, no class/datatype punning.

I don't think this is a very convincing argument, as exactly the cases  
of punning that are currently already prohibited are not very  
intuitive. Having just class/individual punning is hard to defend (in  
particular because, at least in my view, most cases for class/ 
individual punning is just bad practice)

-Rinke

-----------------------------------------------
Drs. Rinke Hoekstra

Email: hoekstra@uva.nl    Skype:  rinkehoekstra
Phone: +31-20-5253499     Fax:   +31-20-5253495
Web:   http://www.leibnizcenter.org/users/rinke

Leibniz Center for Law,          Faculty of Law
University of Amsterdam,            PO Box 1030
1000 BA  Amsterdam,             The Netherlands
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Received on Monday, 30 June 2008 18:46:46 UTC