On quantum methods in the classical theory of representations

Summary: "An elementary introduction to the theory of Drinfelʹd-Jimbo algebras is given, including the famous `crystallization method' of M. Kashiwara and its applications. The exposition is based on a study of the so-called Schubert filtration of the underlying Serre algebras. An application to the classical reduction problem is considered for the case of finite-dimensional representations of semisimple Lie algebras."