ADK@MIT-MC 04/12/82 9:04pm  For information only:
[Bugs in GENDIFF -- SHARE2;GENDIF >]
(1) gendiff(x*(x-a),x,j);
    This asks "Is J - I an integer?", which is hard for the user to answer 
    as I is a system generated dummy summation index (which has, in general, 
    indefinite sign anyhow).
(2) The answer for the above example involves the silly quantity diff(x,x,i),
    which is clearly kdelta(i-1)+x*kdelta(i) for positive integer
    values of i.  This information should be used by SUM as well.
As nobody else is likely to care about these bugs, and I don't really care that
much myself, this note is just for your information.  I might fix up GENDIFF
someday, but I make no promises!