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Re: Comment on rdf concepts (RDF-ISSUE-140)

From: Andy Seaborne <andy@apache.org>
Date: Wed, 07 Aug 2013 23:36:41 +0100
Message-ID: <5202CBF9.4020802@apache.org>
To: public-rdf-wg@w3.org
On 07/08/13 21:02, Markus Lanthaler wrote:
> On Monday, August 05, 2013 6:29 PM, Ivan Herman wrote:
>> I have a question/comment on this:
>>
>> [[
>> 4.1 RDF Dataset Comparison
>>
>> Two RDF datasets (the RDF dataset D1 with default graph DG1 and named
>> graph NG1 and the RDF dataset D2 with default graph DG2 and named graph
>> NG2) are dataset-isomorphic if and only if:
>>
>> 	. DG1 and DG2 are graph-isomorphic;
>> 	. For each (n1,g1) in NG1, there exists (n2,g2) in NG2 such that
>> n1=n2 and g1 and g2 are graph-isomorphic;
>> 	. For each (n2,g2) in NG2, there exists (n1,g1) in NG1 such that
>> n1=n2 and g1 and g2 are graph-isomorphic.
>>
>> ]]
>>
>> A graph name can now be a blank node. Wouldn't it be appropriate to use
>> the 'M' mapping of section 3.6 for the graph names, too? Or are we
>> deliberately silent on this?
>
> Hmm... I'm not sure, it would probably make sense and be consistent with the
> rest. On the other hand, since the graph names are just labels it may not
> make much sense because you could argue that two blank node "labels" will
> never match as they are dataset-local.

This is defining "dataset-isomorphic" (i.e. it's a data structure 
matter, not "equality") so the graph label should be included in the 
isomorphism-ness.

	Andy

PS Testing needs this.

> Anyway, I've opened ISSUE-140 to keep track of this:
>    https://www.w3.org/2011/rdf-wg/track/issues/140
>
>
> Cheers,
> Markus
>
>
> --
> Markus Lanthaler
> @markuslanthaler
>
>
>
>
>
Received on Wednesday, 7 August 2013 22:37:10 UTC

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