Re: Non-Commutative calculations in Calc, Revisited

[Neon Absentius <absent@sdf.lonestar.org>]

On Thu, Oct 06, 2005 at 08:15:10PM -0500, Luc Teirlinck wrote:
>     In any case I do think that is a good idea to have a command
>     that assumes that all variables are square matrices or, in the
>     abstract language, that any two elements are composable.
> 
> As I already pointed out in my follow-up, does `Meta-N m v' not do that?
> (It assumes that all matrices are N by N square matrices.)
> I am not sure whether my follow-up actually got posted, which is why I
> am using email now.
> 

Yes indeed assuming that all matrices are square matrices *of a given
size* does solve the problem of "poor man's non-commutative mode".
And there we can safely use the rule about the inverse of a product.
Thanks for pointing this out and for taking the extra pain to email me
about it so that I can take the message for sure!

BTW my statement that you quoted as it stands it's not true: even if
we assume that all matrices are square still we cannot necessarily
compose them unless they have the same dimensions!

Still it might be usefull to have an assmption that all variables are
square matrices of *unspecified* dimension.

PS. I reply in the group/list since it is not sure whether your post
    will eventually show up.

> Sincerely,
> 
> Luc.

-- 
 There is no national science just as there is no national
multiplication table; what is national is no longer science.
         -- Anton Checov