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Re: commuting and non-commuting symbols

  • To: mathgroup at smc.vnet.net
  • Subject: [mg31365] Re: [mg31361] commuting and non-commuting symbols
  • From: Andrzej Kozlowski <andrzej at tuins.ac.jp>
  • Date: Wed, 31 Oct 2001 03:30:55 -0500 (EST)
  • Sender: owner-wri-mathgroup at wolfram.com

Try <http://www.math.ucsd.edu/~ncalg/>. You may well find what you want, 
particularly if you are using one of the operating systems they support. 
In fact their non-commutative algebra package needs only Mathematica 2.2 
on any platform, but the non-commutative Groebner basis (which for me is 
much more interesting) is a compiled C++ code.

The alternative is to develop everything yourself. I have developed my 
own non-commutative package for doing computations in mod p cohomology 
rings of spaces. In this case when p is odd odd dimensional cohomology 
classes anti-commute. This works quite well, but I have not tried to do 
anything with matrices.

Andrzej Kozlowski
Toyama International University
JAPAN
http://platon.c.u-tokyo.ac.jp/andrzej/

On Tuesday, October 30, 2001, at 06:35  PM, Ian Swanson wrote:

>
> Hi
>
> My research group is trying to use Mathematica to simplify and verify 
> some
> complicated expressions that combine various parameters living in
> different spaces.  Basically, we need to be able to label certain 
> symbols
> as commuting and certain others as non-commuting (ie. Grassman numbers).
> We then need to perform standard matrx multiplication with this mixture 
> of
> commuting and non-commuting variables -- and have Mathematica simplify 
> the
> resulting expressions as much as possible.  Can anyone help??
>
> Thank you,
> Ian
>
> ______________________________
> | Ian J Swanson              |
> | Theoretical Physics        |
> | 253 Lauritsen              |
> | swanson at theory.caltech.edu |
> | office: 626.395.2615       |
> | cell: 626.230.1882         |
> |____________________________|
>
>
>
>



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