Well, yes, "." is non-commutative and "*" is commutative.
As far as I know, there is no standard way to factor non-commutative
polynomials in Maxima.
-s
On Wed, Aug 3, 2011 at 04:43, Zbigniew Komarnicki <cblasius at gmail.com>wrote:
> On Tuesday 02 of August 2011 18:18:32 you wrote:
> > Hello,
> >
> > how to simplify matrix equation 'e2' to obtain back 'e1' ?
> > A,B,C are matrices.
> >
> > matrix_element_mult: "."$
> > e1: A.(B+C);
> > /*
> > A . (C + B)
> > */
> > e2: expand(e1);
> > /*
> > A . C + A . B
> > */
>
> I found that it can be done by 'subst' and 'collectterms' commands. But
> with
> this is a problem, because sometimes the order of matrices are not
> preserved.
>
> e3: subst("*",".",e2);
> /*
> A C + A B
> */
> e4: collectterms(e3,A);
> /*
> A (C + B)
> */
> e5: subst(".","*",e4);
> /*
> A . (C + B)
> */
>
> Is there any chance that 'collecterms' or 'ratcoef' and other command for
> simplifying matrices equations will be work in future Maxima releases (with
> matrices equations) ? And/Or with 'transpose' as I asked
> http://www.math.utexas.edu/pipermail/maxima/2010/021970.html
>
> I'm still beginner in Maxima and I work with Maxima only from time to time.
>
> Thank you for your time and great work.
>
> Zbigniew
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