Hi there,

Just to give you a feedback, below is the reply I received from Maplesoft.

Antonio.

......

Currently something like this is not readily available in Maple; the difficulties
are that Maple processes the arguments at different times. For instance the diff
command in Maple only operates on "names", and will take the derivative of an
expression with respect to the give name. If the name is not present then 0 is
returned.

The purpose of the sum command is not to represent sums of undetermined length as a
data structure, but to find a closed form for a sum (i.e., get rid of the summation
sign.)

What would be required here is a representation of something similar to a list of
undetermined length or a matrix of undetermined dimension, which Maple doesn't
support.

It may be possible to define your own differentiation procedure which will do this.
I would recommend that you review the Maple help page for "proc" which may help you
should you choose to do this.

....

It seems that TDtools can be downloaded from:

http://www.mirrorservice.org/sites/ftp.inf.ethz.ch/pub/software/maple/5.3/share/

Antonio.