This preprint develops the tau-function face of derivative-order geometry and explores its connections with Painleve equations. It defines Hamiltonian derivative-order ladders and sigma-form closure relations for ladder flows. The paper derives bilinear (Hirota) transmutation formulas and extends derivative-order geometry to multitime tau ladders associated with integrable hierarchies. It also establishes exact sigma-state recovery from finite ladder windows.
Mohammad Abu-Ghuwaleh (Tue,) studied this question.