Summation in Mathematica

*To*: mathgroup at smc.vnet.net*Subject*: [mg130590] Summation in Mathematica*From*: Ben Blomberg <bblomberg at mail.bradley.edu>*Date*: Wed, 24 Apr 2013 07:03:54 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-outx@smc.vnet.net*Delivered-to*: mathgroup-newsendx@smc.vnet.net

Hello All, I am trying to understand a piece of code I found but I am stuck on this summation. This is part of a larger do loop over n. UnderoverscriptBox[\(\[Sum]\), \(m = \(-10\)\), \(10\)]\(\(eigenfunctionsort[n, j]\)[\([m + 11]\)] Exp[I*2*\[Pi]*m*x/dp]\)\),{j,1,21}] What I mainly do not understand is what is happening with the [m+11]. Is that being multiplied with eigen function sort with each step in the sum, or is that simply adding 11 to m at each step in the sum? Thanks Ben