Formula that contain only one of the Harmony or the Gradation will prove to be correct using an integral differential method even though it is only have the “half correct”. For that, you must complete the proof of your formula using the algebra.
In detail, if your formula only has the Harmony, then the truth of your formula only applies if you have a set or random variable whose exact nature is not affected at all by the other sets or random variables that are around it. In addition, the same index of the sets that you observe, actually have the nature that are not exactly the same if the number of elements in your sets or random variables are not the same.
Conversely, if your formula only has the Gradation, then on a set or random variable that you observe there are many elements which have the same index even though they don’t have exactly the same nature.