This book gives an exposition of the fundamentals of the theory of
linear representations of ?nite and compact groups, as well as elements
of the t- ory of linear representations of Lie groups. As an application
we derive the Laplace spherical functions. The book is based on lectures
that I delivered in the framework of the experimental program at the
Mathematics-Mechanics Faculty of Moscow State University and at the
Faculty of Professional Skill Improvement. My aim has been to give as
simple and detailed an account as possible of the problems considered.
The book therefore makes no claim to completeness. Also, it can in no
way give a representative picture of the modern state of the ?eld under
study as does, for example, the monograph of A. A. Kirillov [3]. For a
more complete acquaintance with the theory of representations of ?nite
groups we recommend the book of C. W. Curtis and I. Reiner [2], and
for the theory of representations of Lie groups, that of M. A. Naimark
[6]. Introduction The theory of linear representations of groups is
one of the most widely - pliedbranchesof algebra. Practically every
timethatgroupsareencountered, their linear representations play an
important role. In the theory of groups itself, linear representations
are an irreplaceable source of examples and a tool for investigating
groups. In the introduction we discuss some examples and en route we
introduce a number of notions of representation theory. 0. Basic Notions
0. 1.