Offering the insights of L.S. Pontryagin, one of the foremost thinkers in modern mathematics, the second volume in this four-volume set examines the nature and processes that make up topological groups. Already hailed as the leading work in this subject for its abundance of examples and its thorough explanations, the text is arranged so that readers can follow the material either sequentially or schematically. Stand-alone chapters cover such topics as topological division rings, linear representations of compact topological groups, and the concept of a lie group.

Springer-Verlag has invited me to bring out my Selected Works. Being aware that Springer-Verlag enjoys high esteem in the scientific world as a reputed publisher, I have willingly accepted the offer. Immediately, I was faced with two problems. The first was that of acquaint ing the reader with the important stages in my scientific aetivities. For this purpose, I have included in the Selected Works eertain of my early works that have greatly influeneed my later studies. For the same reason, I have also in cluded in the book those works that contain the first, erude versions of the proofs for many of my basic theorems. The second problem was that of giving the reader the best possible opportunity to familiarize himself with the most important results and to learn to use my method. For this reason I have included the later improved versions of the proofs for my basic results, as weil as the monographs The Method of Trigo nometric Sums in Number Theory (Seeond Edition) and Special Variants of the Method of Trigonometric Sums."

The present book contains three articles: "Systems of Linear Differential Equations," by V. P. Palamodov; "Fredholm Operators and Their Generalizations," by S. N. Krachkovskii and A. S. Di kanskii; and "Representations of Groups and Algebras in Spaces with an Indefinite Metric" by M. A. Naimark and R. S. Ismagilov. In the fi.rst article the accent is on those characteristics of systems of differential equations which distinguish the systems from the scalar case. Considerable space is devoted in particular to "nonquadratic systems," a topic that has very recently stimulated interest. The second article is devoted to the algebraic aspects of the theory of operators (determinant theory in particular) in Banach and linear topological spaces. The third article reflects the present state of the art in the given area of the theory of representations, which has been re ceiving considerable attention in connection with its applications in physics (particularly in quantum field theory) and in the theory of differential equations."

This volume contains five review articles, two in the Algebra part and three in the Geometry part, surveying the fields of cate gories and class field theory, in the Algebra part, and of Finsler spaces, structures on differentiable manifolds, and packing, cover ing, etc., in the Geometry part. The literature covered is primar Hy that published in 1964-1967. Contents ALGEBRA CATEGORIES ............... . 3 M. S. Tsalenko and E. G. Shul'geifer 1. Introduction........... 3 2. Foundations of the Theory of Categories . . . . . 4 3. Fundamentals of the Theory of Categories . . . . . 6 4. Embeddings of Categories ... . . . . . . . . . . . . 14 5. Representations of Categories . . . . . . . . . . . . . 16 6. Axiomatic Characteristics of Algebraic Categories . . . . . . . . . . . . . . . . . . . . . . . . . . 18 7. Reflective Subcategories; Varieties. . . 20 8. Radicals in Categories . . . . . . . 24 9. Categories with Involution. . . . . . 29 10. Universal Algebras in Categories . 30 11. Categories with Multiplication . . . 34 12. Duality of Functors. .. ....... 37 13. Homotopy Theory . . . . .. ........... 39 14. Homological Algebra in Categories. . . . . . 41 15. Concrete Categories . . . . .. ......... 44 16. Generalizations.. . . . . . . 45 Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 CLASS FIELD THEORY. FIELD EXTENSIONS. . . . . . . . 59 S. P. Demushkin 66 Literature Cited vii CONTENTS viii GEOMETRY 75 FINSLER SPACES AND THEIR GENERALIZATIONS .."

This volume contains five review articles, three in the Al gebra part and two in the Geometry part, surveying the fields of ring theory, modules, and lattice theory in the former, and those of integral geometry and differential-geometric methods in the calculus of variations in the latter. The literature covered is primarily that published in 1965-1968. v CONTENTS ALGEBRA RING THEORY L. A. Bokut', K. A. Zhevlakov, and E. N. Kuz'min 1. Associative Rings. . . . . . . . . . . . . . . . . . . . 3 2. Lie Algebras and Their Generalizations. . . . . . . 13 ~ 3. Alternative and Jordan Rings. . . . . . . . . . . . . . . . 18 Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25 MODULES A. V. Mikhalev and L. A. Skornyakov 1. Radicals. . . . . . . . . . . . . . . . . . . 59 2. Projection, Injection, etc. . . . . . . . . . . . . . . . . . . 62 3. Homological Classification of Rings. . . . . . . . . . . . 66 4. Quasi-Frobenius Rings and Their Generalizations. . 71 5. Some Aspects of Homological Algebra . . . . . . . . . . 75 6. Endomorphism Rings . . . . . . . . . . . . . . . . . . . . . 83 7. Other Aspects. . . . . . . . . . . . . . . . . . . 87 Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . , 91 LATTICE THEORY M. M. Glukhov, 1. V. Stelletskii, and T. S. Fofanova 1. Boolean Algebras . . . . . . . . . . . . . . . . . . . . . " 111 2. Identity and Defining Relations in Lattices . . . . . . 120 3. Distributive Lattices. . . . . . . . . . . . . . . . . . . . . 122 vii viii CONTENTS 4. Geometrical Aspects and the Related Investigations. . . . . . . . . . . . * . . * . . . . . . . . . * 125 5. Homological Aspects. . . . . . . . . . . . . . . . . . . . . . 129 6. Lattices of Congruences and of Ideals of a Lattice . . 133 7. Lattices of Subsets, of Subalgebras, etc. . . . . . . . . 134 8. Closure Operators . . . . . . . . . . . . . . . . . . . . . . . 136 9. Topological Aspects. . . . . . . . . . . . . . . . . . . . . . 137 10. Partially-Ordered Sets. . . . . . . . . . . . . . . . . . . . 141 11. Other Questions. . . . . . . . . . . . . . . . . . . . . . . . . 146 Bibliography. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 148 GEOMETRY INTEGRAL GEOMETRY G. 1. Drinfel'd Preface . . . . . . . . .

This volume contains two review articles: "Stochastic Pro gramming" by Vo V. Kolbin, and "Application of Queueing-Theoretic Methods in Operations Research, " by N. Po Buslenko and A. P. Cherenkovo The first article covers almost all aspects of stochastic programming. Many of the results presented in it have not pre viously been surveyed in the Soviet literature and are of interest to both mathematicians and economists. The second article com prises an exhaustive treatise on the present state of the art of the statistical methods of queueing theory and the statistical modeling of queueing systems as applied to the analysis of complex systems. Contents STOCHASTIC PROGRAMMING V. V. Kolbin Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1. The Geometry of Stochastic Linear Programming Problems. . . . . . . . . . . . . . . . . . . . 5 2. Chance-Constrained Problems . . . . . . . . . 8 3. Rigorous Statement of stochastic Linear Programming Problems . . . . . . . . . . 16 4. Game-Theoretic Statement of Stochastic Linear Programming Problems. . . . . . . . 18 5. Nonrigorous Statement of SLP Problems . . . 19 6. Existence of Domains of Stability of the Solutions of SLP Problems . . . . . . . . . 29 7. Stability of a Solution in the Mean. . . . . . . . . . . . 30 8. Dual Stochastic Linear Programming Problems. . . 37 9. Some Algorithms for the Solution of Stochastic Linear Programming Problems . . . . . . . . . . 40 10. Stochastic Nonlinear Programming: Some First Results . . . . . . . . . . . . . . . . . . . . . . 42 11. The Two-Stage SNLP Problem. . . . . . . . . . . . 47 12. Optimality and Existence of a Plan in Stochastic Nonlinear Programming Problems. 58 Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . ."

This work is a continuation of earlier volumes under the heading "Probability Theory, Mathematical Statistics, and Theo retical Cybernetics," published as part of the "Itogi Nauki" series. The present volume comprises a single review article, en titled "Reliability of Discrete Systems," covering material pub lished mainly in the last six to eight years and abstracted in "Referativnyi Zhurnal-Matematika" (Soviet Abstract Journal in Mathematics). The bibliography encompasses 313 items. The editors welcome inquiries regarding the present volume or the format and content of future volumes of the series; corre spondence should be sent to the following address: Otdel Matemat ika (Mathematics Section), Baltiiskaya ul., 14, Moscow, A-219. v Contents RELIABILITY OF DISCRETE SYSTEMS M. A. Gavrilov, V. M. Ostianu, and A. I. Potekhin Introduction . . . . . . . . . . . . . . . . . . . . . . .. . . 1 . . . . . . CHAPTER 1. Assurance of Infallibility in Discrete Systems........ . . . . . . . . .. . . . 5 1. State of the Art . ....... .................. 5 2. Basic Definitions, Concepts, and Problem Formulations.. 6 3. Redundancy Models. . . . . . . . . . . . . . . . . . . . . 10 . . . 4. Composition Methods ........................ 17 5. Majority Methods . . . . . . . . . . . . . . . . . . . . . . 27 . . . . 6. Methods Using the Interweaving Model. . . . . . . . . .. . . 35 7. Methods Using Effective-Coding Models. . . . . . . . .. . . 38 CHAPTER II. Assurance of Stability in Discrete System s. . . . . . . . . . . . . . . . . . . . . .. . . 63 . . . . . 1. Basic Concepts and Definitions . . . . . . . . . . . . .. . . 63 . . 2. Elimination of Inadmissible I-Races. . . . . . . . . . .. . . 69 . 3. Elimination of Inadmissible E-Races . . . . . . . . . .. . . 70 . 4. Elimination of Inadmissible M-Races . . . . . . . . . .. . . 73 . 5. Elimination of Inadmissible L-Races . . . . . . . . . .. . . 86 ."

Since the early work of Gauss and Riemann, differential geometry has grown into a vast network of ideas and approaches, encompassing local considerations such as differential invariants and jets as well as global ideas, such as Morse theory and characteristic classes. In this volume of the Encyclopaedia, the authors give a tour of the principal areas and methods of modern differential geomerty. The book is structured so that the reader may choose parts of the text to read and still take away a completed picture of some area of differential geometry. Beginning at the introductory level with curves in Euclidian space, the sections become more challenging, arriving finally at the advanced topics which form the greatest part of the book: transformation groups, the geometry of differential equations, geometric structures, the equivalence problem, the geometry of elliptic operators. Several of the topics are approaches which are now enjoying a resurgence, e.g. G-structures and contact geometry. As an overview of the major current methods of differential geometry, EMS 28 is a map of these different ideas which explains the interesting points at every stop. The authors' intention is that the reader should gain a new understanding of geometry from the process of reading this survey.

Graphs drawn on two-dimensional surfaces have always attracted researchers by their beauty and by the variety of difficult questions to which they give rise. The theory of such embedded graphs, which long seemed rather isolated, has witnessed the appearance of entirely unexpected new applications in recent decades, ranging from Galois theory to quantum gravity models, and has become a kind of a focus of a vast field of research. The book provides an accessible introduction to this new domain, including such topics as coverings of Riemann surfaces, the Galois group action on embedded graphs (Grothendieck's theory of "dessins d'enfants"), the matrix integral method, moduli spaces of curves, the topology of meromorphic functions, and combinatorial aspects of Vassiliev's knot invariants and, in an appendix by Don Zagier, the use of finite group representation theory. The presentation is concrete throughout, with numerous figures, examples (including computer calculations) and exercises, and should appeal to both graduate students and researchers.

The book gives a systematic exposition of the diverse ideas and methods in the area, from algebraic topology of manifolds to invariants arising from quantum field theories. The main topics covered include: constructions and classification of homology 3-spheres, Rokhlin invariant, Casson invariant and its extensions, and Floer homology and gauge-theoretical invariants of homology cobordism. Many of the topics covered in the book appear in monograph form for the first time. The book gives a rather broad overview of ideas and methods and provides a comprehensive bibliography. The text will be a valuable source for both the graduate student and researcher in mathematics and theoretical physics.

Graphs drawn on two-dimensional surfaces have always attracted researchers by their beauty and by the variety of difficult questions to which they give rise. The theory of such embedded graphs, which long seemed rather isolated, has witnessed the appearance of entirely unexpected new applications in recent decades, ranging from Galois theory to quantum gravity models, and has become a kind of a focus of a vast field of research. The book provides an accessible introduction to this new domain, including such topics as coverings of Riemann surfaces, the Galois group action on embedded graphs (Grothendieck's theory of "dessins d'enfants"), the matrix integral method, moduli spaces of curves, the topology of meromorphic functions, and combinatorial aspects of Vassiliev's knot invariants and, in an appendix by Don Zagier, the use of finite group representation theory. The presentation is concrete throughout, with numerous figures, examples (including computer calculations) and exercises, and should appeal to both graduate students and researchers.

Since the early work of Gauss and Riemann, differential geometry has grown into a vast network of ideas and approaches, encompassing local considerations such as differential invariants and jets as well as global ideas, such as Morse theory and characteristic classes. In this volume of the Encyclopaedia, the authors give a tour of the principal areas and methods of modern differential geomerty. The book is structured so that the reader may choose parts of the text to read and still take away a completed picture of some area of differential geometry. Beginning at the introductory level with curves in Euclidian space, the sections become more challenging, arriving finally at the advanced topics which form the greatest part of the book: transformation groups, the geometry of differential equations, geometric structures, the equivalence problem, the geometry of elliptic operators. Several of the topics are approaches which are now enjoying a resurgence, e.g. G-structures and contact geometry. As an overview of the major current methods of differential geometry, EMS 28 is a map of these different ideas which explains the interesting points at every stop. The authors' intention is that the reader should gain a new understanding of geometry from the process of reading this survey.

Homology 3-sphere is a closed 3-dimensional manifold whose homology equals that of the 3-sphere. These objects may look rather special but they have played an outstanding role in geometric topology for the past fifty years. The book gives a systematic exposition of diverse ideas and methods in the area, from algebraic topology of manifolds to invariants arising from quantum field theories. The main topics covered are constructions and classification of homology 3-spheres, Rokhlin invariant, Casson invariant and its extensions, including invariants of Walker and Lescop, Herald and Lin invariants of knots, and equivariant Casson invariants, Floer homology and gauge-theoretical invariants of homology cobordism. Many of the topics covered in the book appear in monograph form for the first time. The book gives a rather broad overview of ideas and methods and provides a comprehensive bibliography. It will be appealing to both graduate students and researchers in mathematics and theoretical physics.

Among the finest achievements in modern mathematics are two of L.S. Pontryagin's most notable contributions: Pontryagin duality and his general theory of characters of a locally compact commutative group. This book, the first in a four-volume set, contains the most important papers of this eminent mathematician, those which have influenced many generations of mathematicians worldwide. They chronicle the development of his work in many areas, from his early efforts in homology groups, duality theorems, and dimension theory to his later achievements in homotopic topology and optimal control theory.

Algebraic and Differential Topology presents in a clear, concise, and detailed manner the fundamentals of homology theory. It first defines the concept of a complex and its Betti groups, then discusses the topolgoical invariance of a Betti group. The book next presents various applications of homology theory, such as mapping of polyhedrons onto other polyhedrons as well as onto themselves. The third volume in L.S. Pontryagin's Selected Works, this book provides as many insights into algebraic topology for today's mathematician as it did when the author was making his initial endeavors into this field.