Approximate Solutions of Partial Differential Operators  (English, Paperback, Gramchev Todor V.)

Microlocal analysis has been a fast developing field. In this book, the authors publish their research results in a summarized form. They deal with the following themes: asymptotic solutions for several classes of linear PDO with multiple characteristics; applications to microlocal solvability and hypoellipticity of the same classes of operators; solvability and hypoellipticity on the torus including construction of global parametrices; applications of the asymptotic methods and Gevrey microlocal analysis to the billiard ball map; and a survey of results in the domain of hypoellipticity and solvability in connection with the construction of asymptotic solutions.