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Re: Blank node identifiers in FILTER clauses (oops)

From: Enrico Franconi <franconi@inf.unibz.it>
Date: Mon, 17 Jul 2006 22:45:24 +0200
Message-Id: <F6609A1C-090C-4FDD-AF05-E3D6647463C7@inf.unibz.it>
To: RDF Data Access Working Group <public-rdf-dawg@w3.org>


On 17 Jul 2006, at 22:41, Enrico Franconi wrote:
>> I'm really surprised this is not how people currently handle OWL
>> semantics. bNodes are perfect for this.
>
> Why does OWL-DL (and the whole literature and practice of  
> databases) consider bnodes (aka existential variables) in the  
> answer set?

I meant:

Why does *NOT* OWL-DL (and the whole literature and practice of  
databases) consider bnodes (aka existential variables) in the answer  
set?

> Because answers would not be unique anymore (there would be  
> infinitely many different answers to a query to a dataset), and  
> most horribly, some of them may be infinitely long.
>
>> If anyone wrote a backward-chaining OWL engine, it seems they'd  
>> have to do this.
>
> I hope I convinced you. Backward chaining is irrelevant here, we  
> are talking about sound and complete reasoners wrt OWL-DL semantics.
>
> cheers
> --e.
>
Received on Monday, 17 July 2006 20:45:37 GMT

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