Re: Non-commutative symbolic multiplication in Calc

[Roland Winkler <winkler@tfkp07.physik.uni-erlangen.de>]

Neon Absentius <absent@sdf.lonestar.org> writes:

>> I doubt that you will get what you want when you just remove the
>> assumption that multiplication is commutative.
>
> Depends on what do you mean by "just" by "remove" and by
> "assumption".  When I say "suspend the assumption" I mean
> (obviously) to also suspend its consequences, for example there
> should be a "left" and a "right" division. It depends also on what I
> want, which (at the moment of writing at least) is rather modest, I
> will be happy if I am able to work on a free group (or a tensor
> algebra) and define relations as rewrite rules.
>
> Ideally the multiplication should not be assumed commutative (or the
> variables invertible) unless explicitly declared so.

Emacs calc (the way I look at it) is designed to be a powerful,
advanced calculator. But it is not a computer algebra system which I
would use to address the kind of problem you are talking about..

For example. take a look at Maxima, http://www.ma.utexas.edu/maxima.html.
It's now under GPL, and it even has a nice emacs interface.

Roland