to_poly



On 6/27/07, Barton Willis <willisb at unk.edu> wrote:

> I placed a new topoly (renamed to_poly) in CVS

Thanks a lot for working on this, Barton.
I think it will find a lot of uses.

> to_poly returns a list with two members. The second list member gives
> conditions on the variables
>
>   (%i1) e : to_poly(abs(x)-8);
>   (%o1) [[%g10-8,%g10^2-x^2],[carg(%g10)=0]]

It seems like this could be more clearly expressed as

  if carg(%g10)=0 then [%g10-8,%g10^2-x^2]

or some other conditional expression.

>   (%i9) perfect_p(n) := is(n = apply("+",
>   listify(disjoin(n,divisors(n)))))$

Hmm. It seems like it would be useful to allow the second
argument of apply to be a set when the first argument is an
n-ary commutative operator (or maybe just commutative).
Just daydreaming here.

best,
Robert