Operator Theory and Ill-Posed Problems

The book is based on the course of lectures on calculus and functional analysis and several special courses given by the authors at Novosibirsk State University. It also includes results of research carried out at the Institute of Mathematics of the Siberian Branch of the Russian Academy of Sciences. A brief introduction to the language of set theory and elements of abstract, linear, and multilinear algebra is provided. The language of topology is introduced and fundamental concepts of analysis for vector spaces and manifolds are described in detail. The most often used spaces of smooth and generalized functions, their transformations, and the classes of linear and nonlinear operators are considered. Special attention is given to spectral theory and the fixed point theorems. A brief presentation of degree theory is provided. The part devoted to ill-posed problems includes a description of partial differential equations, integral and operator equations, and problems of integral geometry. The book can serve as a textbook or reference on functional analysis. It contains many examples. It can also be of interest to specialists in the above fields.