Possible error in the SPARQL 1.1 spec

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Possible error in the SPARQL 1.1 spec

Bernardo Cuenca Grau-4
Dear all,

I would like to report a possible error in the SPARQL 1.1 query language document, which does not seem to be reflected in the accompanying list of errata.

The possible error in question is in Section 18.6 (Evaluation Semantics). If we look at the evaluation of Aggregates 

eval(D(G), Aggregation(exprlist, func, scalarvars, P))

We can see that the algebraic function Aggregation takes as last parameter a pattern P. This seems inconsistent with the semantics of the corresponding construct in section 18.5 as well as with the transformation from SPARQL 1.1 into the algebra in Section 18.2.4, which both suggest that P should be replaced by a group. 


There is also some confusion in Section 18.5.1 in the definition of Aggregation, where on the first line {key_1 -> \Omega_1, \ldots, key_n -> \Omega_n } is
referred to as a "multiset", whereas the evaluation of groups given before in the first section produces a "set". 


Kind regards,


Prof. Bernardo Cuenca Grau
Associate Professor and Royal Society Research Fellow
Department of Computer Science
University of Oxford.


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Re: Possible error in the SPARQL 1.1 spec

Andy Seaborne-4
Bernardo,

Thank you for your comments which look to me like the right corrections
to make.

I've recorded this as errata-query-11 in the errata document for the
next revision of SPARQL to include your corrections.

     Andy

On 19/06/15 12:55, Bernardo Cuenca Grau wrote:

> Dear all,
>
> I would like to report a possible error in the SPARQL 1.1 query
> language document, which does not seem to be reflected in the
> accompanying list of errata.
>
> The possible error in question is in Section 18.6 (Evaluation
> Semantics). If we look at the evaluation of Aggregates
>
> eval(D(G), Aggregation(exprlist, func, scalarvars, P))
>
> We can see that the algebraic function Aggregation takes as last
> parameter a pattern P. This seems inconsistent with the semantics of
> the corresponding construct in section 18.5 as well as with the
> transformation from SPARQL 1.1 into the algebra in Section 18.2.4,
> which both suggest that P should be replaced by a group.
>
>
> There is also some confusion in Section 18.5.1 in the definition of
> Aggregation, where on the first line {key_1 -> \Omega_1, \ldots, key_n
> -> \Omega_n } is
> referred to as a "multiset", whereas the evaluation of groups given
> before in the first section produces a "set".
>
>
> Kind regards,
>
>
> Prof. Bernardo Cuenca Grau
> Associate Professor and Royal Society Research Fellow
> Department of Computer Science
> University of Oxford.
>
>