On the Monodromy of Meromorphic Cyclic Opers on the Riemann Sphere

We study the monodromy of meromorphic cyclic SL(n, C)-opers on the Riemann sphere with a single pole. We prove that the monodromy map, sending such an oper to its Stokes data, is an immersion in the case where the order of the pole is an even multiple of n. To do this, we develop a method based on the work of M. Jimbo, T. Miwa, and K. Ueno from the theory of isomonodromic deformations. Specifically, we introduce a system of equations that is equivalent to the isomonodromy equations of Jimbo-Miwa-Ueno, but which is adapted to the decomposition of the Lie algebra sl(n, C) as a direct sum of irreducible representations of sl(2, C). Using properties of some structure constants for sl(n, C) to analyze this system of equations, we show that deformations of certain families of cyclic SL(n, C)-opers on the Riemann sphere with a single pole are never infinitesimally isomonodromic.