Book «Continuous groups 22 cmT . 3" is an outstanding work written by outstanding mathematicians Lev Semenovich Pontryagin and Revaz Valerianovich Gamkrelidze .. This is the third part of an extensive work devoted to the theory of continuous groups, which is one of the fundamental areas in mathematics and its applications. This book will be a real find for students, graduate students and researchers interested in algebra, geometry and mathematical analysis. In this book, the authors are deeply immersed in the world of continuous groups, exploring their structure, properties and application in various fields of science. The reader will be able to learn about how continuous groups can be used to describe symmetries in physical systems as well as in other mathematical contexts. Pontryagin and Gamkrelidze not only present theoretical foundations, but also offer many examples and tasks, which makes the material more accessible and understandable. The book will be of interest not only to mathematicians, but also to physicists, engineers and all those who seek to understand how mathematical concepts can be applied to real-world problems. It is suitable for both senior students and professionals working in the field of theoretical physics or applied mathematics. If you are interested in mathematics, love to solve complex problems and strive for a deep understanding of the theory, then this book will become a real treasure for you. The topics raised in the book cover a wide range of issues, including topology, algebra, and differential equations. The authors explore how continuous groups can be used to analyze symmetries and invariants, which is a key aspect in physics and other sciences. The book also addresses issues related to the application of continuous groups in relativity theory and quantum mechanics, which makes it particularly relevant to modern research. The style of Pontryagin and Gamkrelidze is clear and logical, which allows the reader to easily follow their thoughts and ideas. They masterfully combine theory and practice, which makes the material not only informative, but also fascinating. If you are familiar with other works of these authors, such as "Continuous Groups" and "Theory of Functional Spaces", then, of course, appreciate this book. In conclusion, "Continuous groups 22 cmT. 3" is not just a textbook, but a real encyclopedia of knowledge that will help the reader not only to master the theory of continuous groups, but also to apply it in various fields of science. This book will become an indispensable assistant for all who seek a deep understanding of mathematics and its application in the real world. Do not miss the opportunity to immerse yourself in the world of continuous groups and discover new horizons of knowledge!