# Relevant help page for: Sum? [duplicate]

When I type Sum into Mathematica, it also offers Sum in the autocomplete dropdown, but when I click the little menu button next to Sum it doesn't take me to any help page. I was hoping this was how to create symbolic sums for manipulation, but when I tried to use it, it turned the text Sum red (instead of the usual black for recognized functions), and I had to restart the kernel before things worked again.

I've read questions such as Meaning of backtick in floating-point literal, but I can't find any reference to how the backtick is used with functions.

What is the meaning of Sum or what is the help file that explains it?

• – Michael E2 Oct 19 '15 at 0:34
• So Sum  is a context for ... for variables? – Travis Bemrose Oct 19 '15 at 0:40
• It's a context for functions internally used by Sum. It's unlikely any them have documentation. Try ?Sum* – Michael E2 Oct 19 '15 at 0:45

To elaborate a bit on Michael's comment, let's first consider this statement from the docs:

Sum and Product use over 100 pages of Wolfram Language code.

Executing ?Sum* will in fact show you some of the internal routines used behind the scenes by the function Sum[]. You, the regular user, are not usually intended to access these by yourself; however, if you look at the names of some of these, you'll see some correspondence with the list of Methods supported by Sum[].

So, for instance,

Sum[i^2, i, Method -> "Polynomial"]


will at some point call

SumSumPolynomialFunction[i^2, i]


P.S. there is also a Product` context.