direct product

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Andeas -<br>
&nbsp;&nbsp;&nbsp; Yes, I should have been more explicit. Thanks for the link (and the
time),<br>
Dick<br>
Andreas J. Guelzow wrote:<br>
<blockquote type="cite"
 cite="mid1093705815.19295.17.camel@kirkman.lab.math.concordia.ab.ca">
  <pre wrap="">Hi Dick,

On Sat, 2004-08-28 at 04:49, richard n. fell wrote:
  </pre>
  <blockquote type="cite">
    <pre wrap="">    Thanks for your reply. Unfortunately, this is not the direct
product.
    </pre>
  </blockquote>
  <pre wrap=""><!---->
Considering most mathematicians will think of the direct product of
groups or universal algebras when they hear the term `direct product'
and may not even realize the use of that term in matrix theory, if you
really want some useful answers it would have been time to explain what
that term in fact means.

Or you could have added a link such as
<a class="moz-txt-link-freetext" href="http://mathworld.wolfram.com/MatrixDirectProduct.html">http://mathworld.wolfram.com/MatrixDirectProduct.html</a>;

Note, that Mathematica does not have a MatrixDirectProduct either which
sort of shows the popularity of that construction.

But similar as shown on that web site, it can probably also easily
calculated in maxima.

(I can't tell you how since I have barely started to use Maxima.)

Andreas
  </pre>
  <blockquote type="cite">
    <pre wrap="">Dick Fell
<a class="moz-txt-link-abbreviated" href="mailto:go_furuya@infoseek.jp">go_furuya@infoseek.jp</a>; wrote:
    </pre>
    <blockquote type="cite">
      <pre wrap="">hi
That is posiible.
for example
(C1) load(diag);
(D1)         /usr/local/share/maxima/5.9.0/share/contrib/diag.mac
(C2) diag([matrix([a0,a1],[a2,a3]),matrix([b1,b2],[b3,b4])]);

                              [ a0  A1  0   0  ]
                              [                ]
                              [ A2  A3  0   0  ]
(D2)                          [                ]
                              [ 0   0   B1  B2 ]
                              [                ]
                              [ 0   0   b3  b4 ]
diag(x),x is list of numbers,or list of matrix.

Gosei Furuya


  
      </pre>
      <blockquote type="cite">
        <pre wrap="">Is there a maxima  share package that computes the direct product of 
matrices? (I can not find any in my maxima).
Thanks,
Dick Fell
        </pre>
      </blockquote>
    </blockquote>
  </blockquote>
</blockquote>
<br>
<br>
<pre class="moz-signature" cols="72">-- 
Richard N. Fell
Martin Fisher School of Physics
Brandeis University
Waltham, Ma 02454
<a class="moz-txt-link-abbreviated" href="mailto:fell@brandeis.edu">fell@brandeis.edu</a>;
</pre>
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