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Re: definition of INDISTINCT

From: Jeen Broekstra <j.broekstra@tue.nl>
Date: Fri, 16 Mar 2007 17:39:25 +0100
Message-ID: <45FAC83D.3000500@tue.nl>
To: Eric Prud'hommeaux <eric@w3.org>
CC: public-rdf-dawg@w3.org

Alright, nitpicking a bit:

Eric Prud'hommeaux wrote:

> persuant to
>   ACTION: ericP to draft text about a LOOSE keyword and run it by w3
>   folks to see if we're abusing the "at risk" mechanism.
> I drafted this section. It was slightly more awkward to not have an
> ALL to lean on, but I think this is pretty well defined:

When/where was this term introduced?

If we decide to add this, I think I would actually prefer LOOSE:
INDISTINCT suggests (to me at least) that it is the opposite of DISTINCT
(which it is not; it would even be acceptable to have the same behavior

> While the DISTINCT modifier ensures that duplicate solutions are
> eliminated from the solution set, INDISTINCT simply permits them to be
> eliminated. The cardinality of any set of variable bindings (solution)
> in an INDISTINCT solution set at least one and not more than the

...*is* at least one...

> cardinality of the solution set with no DISTINCT or INDISTINCT
> modifier.

Perhaps better formulation would be to refer to the cardinality of the
solution set as prescribed by the algebra.

> For example, the query
>   PREFIX foaf:    <http://xmlns.com/foaf/0.1/>
>   SELECT INDISTINCT ?name WHERE { ?x foaf:name ?name }
> may have one, two (shown here) or three solutions:
>   name
>   "Alice"
>   "Alice"

Of course, this only holds for a dataset which holds at least three
solutions for Alice, you might want to make that more explicit in this
paragraph (referring back to the example dataset explicitly?).

Dr. Jeen Broekstra                                          Den Dolech 2
Information Systems Group                                        HG 7.76
Department of Mathematics and Computer Science              P.O. Box 513
Technische Universiteit Eindhoven                      5600 MB Eindhoven
tel. +31 (0)40 247 36 86                                 The Netherlands
Received on Friday, 16 March 2007 16:42:16 UTC

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