Elements of Modern Mathematical Physics

This textbook presents supplementary chapters to the course “Methods of Mathematical Physics” and contains a material on special sections of this course: Calculus of Variations and its applications in classical mechanics; First-Order Partial Differential Equations; the Sturm–Liouville problem for partial differential equations, and pseudo\-differential operators. The textbook can be useful to the graduate students, magisters, and postgraduates specializing in theoretical and mathematical physics. The textbook is intended for students and post-graduates of physical and engineering departments.