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Re: RDF-ISSUE-98 (graph-dataset-semantics-unified): Should the semantics of RDF graphs and the semantics of RDF datasets be combined into one unified semantics? [RDF Semantics]

From: Pat Hayes <phayes@ihmc.us>
Date: Fri, 14 Sep 2012 00:39:00 -0500
Cc: Andy Seaborne <andy.seaborne@epimorphics.com>, public-rdf-wg@w3.org
Message-Id: <266F99E1-0650-4FF2-8392-5768F4BF28C6@ihmc.us>
To: Richard Cyganiak <richard@cyganiak.de>

On Sep 13, 2012, at 7:39 AM, Richard Cyganiak wrote:

> On 13 Sep 2012, at 13:12, Andy Seaborne wrote:
>> We would have to be careful to explain why we then don't have datasets-inside-datasets and "named datasets".  
> It's a somewhat arbitrary restriction in the abstract syntax that makes implementations simpler while still allowing the use cases we care most about to be addressed.
>> It's not a block to the idea but keeping them separate does make it clearer where the boundary is.
> I think that keeping them separate would make the Semantics document more complicated. The Semantics document is complicated enough as it is. I think making it more complicated to account for a syntactic restriction is not a good idea. If writing a semantics that is more general than necessary for the abstract syntax turns out to be simpler, then readers are better served by the simpler thing, IMO.

I agree.

> A related case here is literals-as-subjects, which is a well-motivated restriction that I never would want to remove

Just as an aside, and off-list if you prefer, I would love to hear what these good motivations are. AFAIK, the only motivation for this restriction is a historical vestige of a problem in the RDF/XML striped syntax conventions. 

> , but I'd prefer if the Semantics document would use a generalized notion of RDF graphs that doesn't have the restriction, because that would remove probably a page of pointless and hard-to-understand trickery that is needed to work around the restriction.

More like ten pages, actually, and several long and boring proofs, and several silly but necessary inference rules. 

> At least I personally found that a barrier to understanding the document.

And it was a huge problem when writing the document. 


> Best,
> Richard

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Received on Friday, 14 September 2012 05:39:39 UTC

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