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Re: Sloppy inference rules

From: Ivan Herman <ivan@w3.org>
Date: Thu, 1 Nov 2012 11:13:38 +0100
Cc: "'Pat Hayes'" <phayes@ihmc.us>, "'Guus Schreiber'" <guus.schreiber@vu.nl>, "'RDF WG'" <public-rdf-wg@w3.org>
Message-Id: <01F18977-8E88-4818-BFFC-827023EEB50C@w3.org>
To: Markus Lanthaler <markus.lanthaler@gmx.net>
It is not as clear-cut...

1. There has been lots of discussions and controversies about this (although most of the controversies were on the literal-as-subject and not on the bnode-as-predicate issue). Ie, it is not just some simple editorial change. I have no idea what it would involve in terms of the RDF semantics, let alone OWL. Also, apart from theoretical considerations, we have not seen huge demands from the community to add, say, bnodes as predicates.

2. For the situation that Pat describes the issue is that a rule engine implementing the rules may (well, actually has to) have intermediate steps with triples that violate the restrictions on triples, but then export the valid triples only. I do not see any problem with this.


On Nov 1, 2012, at 10:50 , Markus Lanthaler wrote:

> On Thursday, November 01, 2012 6:56 AM, Ivan Herman wrote:
>> As Antoine notes, the OWL 2 group has faced the same issue for OWL 2
>> RL. I do not see any problem doing that in this case either. I do not
>> think we should reopen, at this point, the bnode-in-predicate and
>> literal-in-subject issue and, with this, using this 'generalized
>> triples for the rules' seems to be the clean approach...
> Honestly it sounds a bit strange to me to simply accept that there is a
> fundamental problem without trying to address it - especially considering
> that the problem has been known since at least 2005 (2002?).
> The other thing that worries me even more is the fact that a number of RDF
> serialization formats are in the process of being standardized right now. At
> least JSON-LD doesn't have this artificial restriction but that was heavily
> criticized by the RDF WG and, as it seems at the moment, we will have to
> introduce it.
> I think there won't be a better point in time to fix this once for all.
> Thanks,
> Markus 

Ivan Herman, W3C Semantic Web Activity Lead
Home: http://www.w3.org/People/Ivan/
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Received on Thursday, 1 November 2012 10:14:01 UTC

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