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Re: Action-164 suggestions (again) for unnamed individuals *in addition* to bnodes

From: Alan Ruttenberg <alanruttenberg@gmail.com>
Date: Wed, 2 Jul 2008 08:58:52 -0400
Message-Id: <EA3AFF75-A0A9-4B71-9DC1-5C2657A59748@gmail.com>
Cc: OWL Working Group WG <public-owl-wg@w3.org>
To: Bijan Parsia <bparsia@cs.man.ac.uk>

On Jul 2, 2008, at 8:33 AM, Bijan Parsia wrote:
> On 2 Jul 2008, at 12:21, Alan Ruttenberg wrote:
>> On Jul 2, 2008, at 7:12 AM, Bijan Parsia wrote:
>>> On 2 Jul 2008, at 12:00, Alan Ruttenberg wrote:
>>>
>> So better would be:
>>
>> UnnamedIndividual([handle] type(owl:Thing))
>>
>> where handle is name for the individual that has scoped within the  
>> ontology only.
>
> Aka bnode ids :)

No. Specifically not, by this proposal. A different syntactic  
category. One that would function, however, in the way you have  
proposed bnodes should (other than the fact that they are not,  
technically, bnodes)

>> Why? The individuals created by the "UnnamedIndividual()"  
>> constructor are not really anonymous - they are named, just not by  
>> the user. So we have tree-shaped restrictions for the  
>> existentials, as in OWL 1, and arbitrary graphs of named  
>> individuals, as before.
>
> If Bnodes have existential semantics and they appear in arbitrary  
> graphs patterns, then we're back to where we started :)

Yes, but I've just said that they can't. Only the the pseudo  
anonymous individuals can appear in arbitrary graphs by this  
proposal. Perhaps I'm not being clear enough. My proposal is, if one  
writes the following:

UnnamedIndividual(myname type(owl:Thing))

That a new guid is created to name this individual, say: owl:uuid/ 
15207c60-4835-11dd-942d-0002a5d5c51b

The statement is processed (by a step immediately after parsing) as  
if it was written as:

Individual(owl:uuid/15207c60-4835-11dd-942d-0002a5d5c51b type 
(owl:Thing))

In addition, within the scope of an the ontology being parsed,  
occurrences of the name "myname", are replaced with owl:uuid/ 
15207c60-4835-11dd-942d-0002a5d5c51b

Absent anything further, on rereading this ontology the editor is  
able to recognize that this is one of those unnamed individuals  
because its name is in the reserved owl namespace and of a specific  
form. It would create a genid, as tools do now, or if the user (or  
tool) wished to remember the previous name they could add a label or  
annotation to do so. If we wished would could define a built-in   
annotation property to record the handle.


>>> It also doesn't address the legacy issue that people use bnodes  
>>> as if they were skolem. We could consider evangelizing not using  
>>> bnodes in RDF when skolem semantics were meant, but I don't see  
>>> that working well anytime soon without a *big* push.
>>
>> True. However my action wasn't to address this. It is certainly an  
>> important element in our discussion of what decision to make, though.
>
> To tie it back to your action, I suspect we might get push back  
> from having pseudo-anonymous individuals that weren't bnodes. I  
> don't know how much, though.
>
> Cheers,
> Bijan.
>
Received on Wednesday, 2 July 2008 12:59:36 UTC

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