U .+k .-(L .+k ) so n +1 A. U.-L. k.u-k . S2 + 3 +1 A. A. 1 2 k .-k . =n f+ 3 3 but since k.u, k and A. are all constants the difference between number of functions and the number of variables is always the same and hence there is no acceleration of variables. There can be no acceleration of variables for a variable index defined by a list since the difference between the number of functions (or function index values) and variables (or variable index values) is always the number of list elements minus one.