Title: Perturbation theory in periodic problems for two-dimensional integrable systems
Description: The perturbation theory of finite-zone solutions of two-dimensional integrable equations is developed. As a special case the theory of perturbations of finite-zone solutions of one-dimensional evolution equations of the Lax type (the Korteweg-de Vries and Sine Gordon equations) is considered. The special theory of two-dimensional periodic operators is surveyed.--
Subjects: Perturbation (Mathematics)