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Question on the SPARQL spec

From: Francis McCabe <frankmccabe@mac.com>
Date: Sun, 28 Oct 2007 11:56:45 -0700
Message-Id: <7D993C86-959D-4BEF-89CB-282F87AC31B1@mac.com>
To: public-rdf-dawg-comments@w3.org

The semantics of LeftJoin read

Definition: LeftJoin
Let Ω1 and Ω2 be multisets of solution mappings and F a filter. We  
define:

LeftJoin(Ω1, Ω2, expr) = Filter(expr, Join(Ω1, Ω2)) set-union Diff 
(Ω1, Ω2, expr)

card[LeftJoin(Ω1, Ω2, expr)](μ) = card[Filter(expr, Join(Ω1, Ω2))] 
(μ) + card[Diff(Ω1, Ω2, expr)](μ)



Presumably, this should read

Definition: LeftJoin

Let Ω1 and Ω2 be multisets of solution mappings and expr a filter.  
We define:

LeftJoin(Ω1, Ω2, expr) = Filter(expr, Join(Ω1, Ω2)) set-union Diff 
(Ω1, Ω2, expr)

card[LeftJoin(Ω1, Ω2, expr)](μ) = card[Filter(expr, Join(Ω1, Ω2))] 
(μ) + card[Diff(Ω1, Ω2, expr)](μ)




Frank McCabe
Received on Sunday, 28 October 2007 18:57:13 GMT

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