Am Samstag, den 15.05.2010, 02:33 -0600 schrieb Robert Dodier:
> On 5/14/10, pbowyer at olynet.com <pbowyer at olynet.com> wrote:
>
> > As you can see from the output, I have an extra term involving p[0] for the
> > FD[i](3,0) function outputs that does not show up if I manually do the
> > calculation. Am I doing something incorrectly, or is there a problem
> > with Maxima?
>
> Yes, it's a bug. Here is a simpler example:
>
> 'sum(0^i, i, 0, n);
> => 0
>
> Depending on what you think is the value of 0^0, that should either
> trigger an error (since Maxima by default believes 0^0 is undefined)
> or 1 (pretty much everyone else in the world).
>
> In the above example, Maxima has assumed that 0^i => 0 without
> looking at the possible values of i. Here is an even simpler example.
>
> 0^i;
> => 0
>
> assume (i >= 0);
> 0^i;
> => 0
>
> I claim neither of these should simplify to 0;
> anyone who believes 0^0 = 1 (and this does seem to be quite
> a lot of people) should agree.
>
> By the way, you're more likely to get people to look at your
> problem if you say "Here is X and here is Y, I thought they
> should be the same but they're not" as opposed to "Here are
> 10 different things, two of which are not equal."
With revision 1.97 of simp.lisp we had a patch to handle the expression
0^a more carefully and more complete.
With revision 1.99 of simp.lisp this patch has been reverted in parts.
Especially, 0^a again simplifies to 0. This had to be done because the
routines of simptimes can not handle unsimplified 0^a expressions.
Therefore, in a next step we have to improve the routines of simptimes
to handle unsimplified 0^a expressions.
Dieter Kaiser