Subject: Re: binomial(x,x) => 1, but binomial(-1,-1) => 0
From: Stavros Macrakis
Date: Fri, 22 Aug 2003 08:58:47 -0400
> (C2) sum(1,k,0,-1);
> (D2) 0
> Note that D2 does not give an error. Very strange.
sum(...,n,n-1) is used as the convention for an empty sum. Otherwise
there is no way to express it. The same convention is followed in
makelist and product.
> Of course, this should be done interactively.
Doing things interactively is appropriate in many cases, and Maxima is
good at that. What I think we need to work on more is the
non-interactive case, where the value involves conditionals or delta
functions or whatever. Unfortunately, Maxima is currently not very well
set up for conditionals. I don't want to discuss this here right now,
but Barton and I have been talking about this, and anyone who's
interested in joining the discussion should write us.
-s