This paper lifts derivative-order geometry to integrable hierarchies by introducing multitime tau ladders that track derivative orders along multiple times. It establishes a universal cube law and shows that Hirota bilinear transmutation generates the full hierarchy. Explicit KP/Toda closures are derived, and a finite Plücker recovery theorem proves that a finite jet suffices to recover the derivative-order spectrum.
Mohammad Abu-Ghuwaleh (Tue,) studied this question.