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Re: range of algebra operators

From: Lee Feigenbaum <lee@thefigtrees.net>
Date: Thu, 25 Oct 2007 11:02:54 -0400
Message-ID: <4720B01E.9010202@thefigtrees.net>
To: Olaf Hartig <hartig@informatik.hu-berlin.de>
CC: public-rdf-dawg-comments@w3.org

Olaf Hartig wrote:
> Hello,
> 
> I'm a bit puzzled what exactly the result of the algebra operators defined in 
> section 12.4 is. Is it a set of solution mappings or a multiset?
> I guess it is a multiset, as suggested by the equations with the cardinalities 
> in the definitions. Additionally, it makes more sense to me (esp. w.r.t. 
> nesting of algebra operators). However, the definitions use braces which 
> suggest sets, because braces are usually used to denote sets.

Hi Olaf,

The result of each operator is a multiset, specified by a set of 
solutions and a mapping from each solution in the set to a cardinality 
value. Each operator's definition gives the set results of the operation 
(in curly braces) and the cardinality of each element of the set.
	
Lee
Received on Thursday, 25 October 2007 15:03:05 GMT

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