“…The construction of the surface of isomonodromic deformations became possible in many respects after the proof of several theorems about the properties of systems of linear differential equations. The method of isomonodromic deformations [4], [5] is used to study nonlinear equations, its idea is to implement a nonlinear equation as an isomonodromic condition of a certain system, and this interpretation provides essential information about the nonlinear equation. Under the surface, we consider the set Σ at points ( )…”