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From "Karsten Konrad" <Karsten.Kon...@xtramind.com>
Subject AW: Vector Space Model in Lucene?
Date Fri, 14 Nov 2003 14:07:52 GMT

Hi,

>>
 vector space is only one of several important ones.
>>

what are these several other important ones?

While Lucene does not give an explicit vector space
representation - you can not efficiently access the vector 
of one document - the index' basic representation is
a reduction of each document to its terms and 
frequencies, hence a mapping into a vector space and hence
a vector space model. The relative term weights (TF/IDF) warp the
space and the vectors, but all of Lucene's search operations 
nevertheless are  operations on a vector space model 
(ok, maybe phrase  search is a bit different as it 
requires an extension by position information).

E.g., searching a term means finding all vectors  that have 
a certain common dimension and ranking means weighting these 
relatively to their angle in vector space. 

KK

Mit freundlichen Grüßen aus Saarbrücken

--

Dr.-Ing. Karsten Konrad
Head of Artificial Intelligence Lab

XtraMind Technologies GmbH
Stuhlsatzenhausweg 3
D-66123 Saarbrücken
Phone: +49 (681) 3025113
Fax: +49 (681) 3025109
konrad@xtramind.com
www.xtramind.com


-----Ursprüngliche Nachricht-----
Von: Chong, Herb [mailto:HChong3@bloomberg.com] 
Gesendet: Freitag, 14. November 2003 14:35
An: Lucene Users List
Betreff: RE: Vector Space Model in Lucene?


does it matter? vector space is only one of several important ones.

Herb....

-----Original Message-----
From: Leo Galambos [mailto:Leo.G@seznam.cz]
Sent: Friday, November 14, 2003 4:00 AM
To: Lucene Users List
Subject: Re: Vector Space Model in Lucene?


Really? And what model is used/implemented by Lucene?

THX
Leo

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