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Re: On Provenance for Queries for Web Data

From: Olaf Hartig <hartig@informatik.hu-berlin.de>
Date: Fri, 21 May 2010 20:25:11 +0200
To: Irini Fundulaki <fundul@ics.forth.gr>
Cc: public-xg-prov@w3.org, Vassilis Christophides <christop@ics.forth.gr>, Grigoris Karvounarakis <gregkar@gmail.com>, Yannis Theoharis <ytheohar@gmail.com>
Message-Id: <201005212025.18654.hartig@informatik.hu-berlin.de>

On Friday 21 May 2010 15:25:01 Irini Fundulaki wrote:
> [...]
> To conclude, first we evaluate the query under the query language
> semantics, and then the evaluation of provenance expressions will
> determine the support of the query result.

Okay - but in this case solution mu_21 will never be discovered because it 
would never be determined based on the query language semantics (assuming
you mean SPARQL semantics). Therefore, you can never evaluate a provenance 
expression for mu_21 to determine the support for it.

> [...]
>  > Okay. However, aren't "abstract provenance models" a special kind of
>  > annotation models. They annotate the source data and solutions with a
>  > provenance expression.
> True.  But we tried to make the distinction more clear since
> in the case of abstract provenance models the annotations are expressions
> on tokens.


>  [...]
>  >> Well, Linked Data is expressed in RDF which are queried with SPARQL.
>  >> Linked Data is a global dataspace where data from different sources are
>  >> integrated and accessed by a large set of users. Consequently, Linked
>  >> Data is an excellent motivation for provenance applications with
>  >> requirements that cannot be fully addressed by annotation-based models
>  >> as we clearly discuss in the paper.
>  >
>  > Sure, it is an excellent motivation. However, you don't work on a
>  > provenance model for Linked Data as you write in your Conclusions
>  > section.
> So, what are the data provenance requirements for Linked Data that are
> not addressed by the provenance models discussed in the paper?

Linked Data is not only about executing SPARQL queries over a set of RDF 
triples that might originate from different sources. I still struggle to see 
what is Linked Data specific about models that describe the provenance
of query executions.


Received on Friday, 21 May 2010 18:26:35 UTC

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