Re: r*r^(k-1) -> r^k / Declaring variable ranges

On Wed, Jun 18, 2008 at 5:14 PM, Gerald Knizia wrote:
> by default, axiom will simplify an expression like "r * r^5" into "r^6".
> However, an expression like "r * r^(k-1)" is untouched and not turned
> into "r^k". How can I change this?

One easy way is using a rule:

(1) -> simplePowers := rule x*x^n == x^(n+1)

              n        n + 1
   (1)  %L x x  == %L x

                    Type: RewriteRule(Integer,Integer,Expression Integer)

(2) -> w:=r*r^(k-1)

           k - 1
   (2)  r r
                    Type: Expression Integer

(3) -> simplePowers w

         k
   (3)  r

                     Type: Expression Integer

Regards,
Bill Page.