Identify K from the basis change with the K in U_p(0)
Show that, for fourth-order Calabi–Yau type differential operators, the rational number K appearing in the generalized change-of-basis ρ equals the coefficient K occurring in the Frobenius matrix U_p(0).
References
Further, we conjecture that the rational number K appearing in this relation is equal to the coefficient K in the matrix U_p(0). We are not aware of counterexamples to this conjecture.
— Solutions of Calabi-Yau Differential Operators as Truncated p-adic Series and Efficient Computation of Zeta Functions
(2604.01191 - Kuusela et al., 1 Apr 2026) in Appendix B