Asymptotics of Linear Differential Equations

The asymptotic theory deals with the problern of determining the behaviour of a function in a neighborhood of its singular point. The function is replaced by another known function ( named the asymptotic function) close (in a sense) to the function under consideration. Many problems of mathematics, physics, and other divisions of natural sci­ ence bring out the necessity of solving such problems. At the present time asymptotic theory has become an important and independent branch of mathematical