Is there any known interpretation of the following expression: Sum[ f (x + j*dx)*Exp[-i 2 Pi j / n], {j, 0, n - 1}]?

Here f(x) is an arbitrary differentiable function and dx is a small increment. I am also interested in the limit of this expression when both n -> Infinite and dx -> 0. I guess the absolute value...

03 March 2013 10,022 4 View