Re: [Maxima] expand/simplify is a BUG in GCL MAXIMA

RJF wrote 
>  I have recently suggested
>  1. Never use the maxima command ev.
>  Let me add to it:
>  2. Never use the maxima command expand except for
>  little demonstration programs which don't do anything
>  serious.

I agree 1,but dose not agree 2.(in case of commutative,I agree.)
Because the command expand is indispensable to define none
commutative algebra ,(for example Clifford Algebra).
Maxima can treat none commutative variables in it's defaults domain.
Almost none of the general purpose symbolic computing system
have not this.

(C1) (a+b) . (a-b);

(D1) 			       (b + a) . (a - b)
(C2) expand(%);

				   		  
(D2) 			  b . a - b    - a . b + a
(C3) (A + a) . (A -a);

(D3) 			       (A + a) . (A - a)
(C4) expand(%);

				    		   
(D4) 			 - A . a + A    + a . A - a

  a . b is none commutative product.(it is OK)
  So long as we  write simplification function under the 
necessity of the defined Algebra,we obtain
various none commutative Algebra.
We can define various products with this.
So to speak expand and "." operator are a  mother for 
various none commutative Algebra.
Of course writting simplification may not be easy.
gamma matrix is one of clifford algebra,most physican don't
care mathematical definitions,more every computer scientists
don't care phisical entity.
So maxima(macsyma)'s design is superior to others.I think.
Wiithout  phisical entity and mathematical definition,
with maxima, we define various algera,so I need expand.


Daniell lemire wrote
> I propose that expand be removed, or fixed. I suspect that if nobobody
>  wants to fix it, the easier path would be to remove it (which I suspect
>  amounts to simply commenting out some code).

No,No,No,We need expand for none commutative Algebra.

Gosei Furuya (go_furuya@infoseek.jp)