On 3/27/17 11:42 AM, Markus Kroetzsch wrote:
On 27.03.2017 15:13, Kingsley Idehen wrote:
On 3/18/17 6:15 PM, Daniel Kinzler wrote:
...

Daniel,

I see Wikidata is a collection of reified RDF Statements. I don't see
how this model differs from RDF's model. It just so happens (in my eyes)
that Wikidata includes description of statements about things which
provides rich metadata, in line with the goals of Wikidata.

Kingsley,

Wikidata is not a collection of reified RDF statements, but it can partially be captured by such a collection. There are many ways of doing this; see [1] for a comparison of some of the more prominent approaches. All of these encodings can "capture" Wikidata in some way, but they are not equivalent in terms of RDF or SPARQL. It would therefore be wrong to claim that any of these possible encodings "is" Wikidata.

Different RDF encodings are not only non-equivalent but also behave very differently in practice. Some queries that work well for one model are very slow or outright impossible to express in another model [1]. One can therefore not say that the encoding is just a detail and that Wikidata somehow "in principle" is RDF anyway.

This said, the current Wikidata RDF export should serve the needs of most people who want to work with an RDF toolchain while having access to most Wikidata content. One cannot get all details from this projection, but one can do most practically useful things.

Regards,

Markus

[1] Daniel Hernández, Aidan Hogan, Markus Krötzsch
Reifying RDF: What Works Well With Wikidata?
In Thorsten Liebig and Achille Fokoue, eds., Proceedings of the 11th International Workshop on Scalable Semantic Web Knowledge Base Systems, volume 1457 of CEUR Workshop Proceedings, 32-47, 2015. CEUR-WS.org
https://iccl.inf.tu-dresden.de/web/Inproceedings3037

Markus,

Let's agree to disagree, for now :) 

-- 
Regards,

Kingsley Idehen	      
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