One more observation, after a look at the HSV<->RGB conversion definitions, the HSV node appears to be redundant, because when S == 0.0 you get a greyscale out, meaning that the correction is based on the V component [== max(R, G, B)] rather than each of RGB being corrected individually as just using a Color_Math node alone to the Pow.

Using a Math_Functions node for the Pow gives the same effect as the combination of HSV and Color_Math nodes.