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 | > |____________________________| > > > >