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completed complexity of unary functions 

git-svn-id: http://galileo.dmi.unict.it/svn/relational/trunk@118 014f5005-505e-4b48-8d0a-63407b615a7c
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LtWorf 2009-04-01 13:37:56 +07:00
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8
complexity
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@ -64,5 +64,11 @@ Notation
1.3 Projection
The projection operation creates a copy of the original relation
using only a subset of its fields. Time for the copy is something
like O(|n|*f) where f is the number of fields to copy.
But that's not all. Since relations are set, duplicated items are not
allowed. So after extracting the wanted elements, it has to check if
the new tuple was already added to the new relation. And this brings
the complexity to O((|n|*f)²).
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