Handling implicit sets would be very nice, but perhaps a bit ambitious
for a first effort. I would be satisfied if Maxima could handle the
kind of explicit multiple sum that Mathematica handles, i.e. an
expression of the form
Sum(expr, {i,i1,i2}, {j,j1,j2}, {k,k1,k2}, ...)
where the limits of the indices are not restricted to be constants, but
later ones can depend on the indices appearing earlier in the list. (Or
the opposite convention).
Robert Dodier wrote:
> On 3/13/07, Kostas Oikonomou <ko at research.att.com> wrote:
>
>> Is there a way to write a double sum in Maxima? E.g.,
>>
>> sum_{1 <= i < j <= n} a[i] * b[j]
>
> Unfortunately no. I would be very interested to have such a thing.
> One solution is to allow something like sum(expr, i, S) where S is
> a set, either explicit (like {a, b, c}) or implicit (like {(i, j) s.t.
> 1 <= i < j <= n}).
> Maxima doesn't recognize implicit sets; I'd like to see that too.
> There remains the problem of telling Maxima what to do with such
> summations, but first we have pick a representation, and just that
> would be a step in the right direction.
>
> FWIW
> Robert