Re: a blank node issue

On 03/02/2011 07:50 PM, Reto Bachmann-Gmür wrote:
> ----- Original message -----
>> On 03/02/2011 07:21 PM, Pat Hayes wrote:
>>>
>>> On Mar 2, 2011, at 9:54 AM, Richard Cyganiak wrote:
>>>
>>>> On 2 Mar 2011, at 14:18, William Waites wrote:
>>>>> maybe some convention or
>>>>> standard for skolemising blank nodes so they can be 
>>>>> referred to might be a good thing?
>>>>
>>>> There is already a convention/standard for skolemising blank nodes:
>>>> just use a URI instead.
>>>
>>> But that subtly changes the RDF, because the URI has global scope. 
>>
>> Is there any practical difference between bnodes and normal nodes,
>> except the scope (and necessity) of their name?
> 
> Yes, a graph with bnodes can potentially be simplified: the same meaning may be expressed with a more lean graph, i.e. with less nodes and triples. If all your nodes are uris you cannot do simplifications with rdf entaillment.

So that in fact means that bnodes are considered from a closed world
scenario, where we assume there are no other references to the node
outside of what we know. On the other hand normal nodes have global
identifier which forces us to consider it from an open world scenario.

To the scoping of the blank nodes: doesn't anyone else think there
should be several types of blank nodes? (example: current graph, current
document, maybe even specific document)

Best,
Jiri

> Cheers,
> Reto
> 
>>
>> Best,
>> Jiri
>>
>>> Pat
>>>
>>>>
>>>> Richard
>>>>
>>>>
>>>>>
>>>>> Cheers,
>>>>> -w
>>>>> -- 
>>>>> William Waites                               <mailto:ww@styx.org>
>>>>> http://river.styx.org/ww/               <sip:ww@styx.org>
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>>>>>
>>>>
>>>>
>>>
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>>
> 
>