Value of the reduced skewness, S₃, obtained at increasing order beyond the mean field. The mean field solution of the Rayleigh-Levy flights model, 3/2, is the same, whatever the index of the spectrum and the shape of the window function. The exact expression of S₃ depends however slightly on the power law index and on the filter shape. They are indicated as dotted lines. One can see that corrections to the mean field solution converge very rapidly to the expected value.