I am trying to solve a double summation problem. But the result I get is different than the one already published in a research paper. Can anyone please find where I am making mistake. I tried the following:
While the correct result is:
For this problem I noticed that the indices of the inner summations were from h to w_i - 1 but it looks like the expression accounts for an extra term since you have w_i - h instead of w_h - 1 - h.