Re: Non-Commutative calculations in Calc, Revisited

[Jay Belanger <belanger@truman.edu>]

Neon Absentius <absent@sdf.lonestar.org> writes:
...
> However I am more interested in the case that there is a *globally*
> defined associative multiplication and I am using the matrix mode as a
> "poor man's no-commutative algebra mode".  In this context my remark 
> makes sence.  I still believe that there is a need for such a mode,
> perhaps a "sub-mode" of the matrix mode where one assumes that all
> matrices are square.  I am not sure how hard this is to implement.
> What do you think Jay?

It shouldn't be hard.

[from a different message]
> 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!

Right, but that's not a problem in Calc.  Similar to how you can't add
matrices A and B unless they're the same size, but in matrix mode the
user can still enter `a+b' and Calc treats it as if it makes sense;
it's implicitly assumed then that they're appropriate sizes.

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

Yes.

Jay