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November 2003

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Subject:
From:
Simon Gollick <[log in to unmask]>
Reply To:
Classification, clustering, and phylogeny estimation
Date:
Thu, 20 Nov 2003 16:40:45 +0100
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Dear Listmembers,

in my final paper I´m dealing with both metric MDS
(Torgersons´s Triadic combinations from his book 1958)
and nonmetric MDS (Kruskal´s algorithm) as "milestones
of MDS". The most important advantage of nonmetric MDS
are the low requirements to data, i.e. the algorithm
requires only ordinal data to reconstruct a
configuration of objects. Nevertheless the procedure
yields metric information within the configuration. My
problem is how to give a reasonable justification for
that fact. I suppose it`s because of the constraints
simultaneously concerning all objects.
What is the minimum number of objects to have no
noticeable difference between an ordinal and an metric
configuration?
Could anyone perhaps give me an statement on this
subject or at least a reference for a quotation?

Many thanks an best regards,

Simon Gollick


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