This collection of papers constitutes a wide-ranging survey of recent developments in differential geometry and its interactions with other fields, especially partial differential equations and mathematical physics. This area of mathematics was the subject of a special program at the Institute for Advanced Study in Princeton during the academic year 1979-1980; the papers in this volume were contributed by the speakers in the sequence of seminars organized by Shing-Tung Yau for this program. Both survey articles and articles presenting new results are included. The articles on differential geometry and partial differential equations include a general survey article by the editor on the relationship of the two fields and more specialized articles on topics including harmonic mappings, isoperimetric and Poincare inequalities, metrics with specified curvature properties, the Monge-Arnpere equation, L2 harmonic forms and cohomology, manifolds of positive curvature, isometric embedding, and Kraumlhler manifolds and metrics. The articles on differential geometry and mathematical physics cover such topics as renormalization, instantons, gauge fields and the Yang-Mills equation, nonlinear evolution equations, incompleteness of space-times, black holes, and quantum gravity. A feature of special interest is the inclusion of a list of more than one hundred unsolved research problems compiled by the editor with comments and bibliographical information.

The book aims to present a comprehensive survey on biharmonic submanifolds and maps from the viewpoint of Riemannian geometry. It provides some basic knowledge and tools used in the study of the subject as well as an overall picture of the development of the subject with most up-to-date important results.Biharmonic submanifolds are submanifolds whose isometric immersions are biharmonic maps, thus biharmonic submanifolds include minimal submanifolds as a subclass. Biharmonic submanifolds also appeared in the study of finite type submanifolds in Euclidean spaces.Biharmonic maps are maps between Riemannian manifolds that are critical points of the bienergy. They are generalizations of harmonic maps and biharmonic functions which have many important applications and interesting links to many areas of mathematics and theoretical physics.Since 2000, biharmonic submanifolds and maps have become a vibrant research field with a growing number of researchers around the world, with many interesting results have been obtained.This book containing basic knowledge, tools for some fundamental problems and a comprehensive survey on the study of biharmonic submanifolds and maps will be greatly beneficial for graduate students and beginning researchers who want to study the subject, as well as researchers who have already been working in the field.

In der Reihe "TEUBNER-ARCHIV zur Mathematik" werden bedeutende klassische Arbeiten kommentiert, mit aktuellen Anmerkungen versehen und durch Literaturhin- weise ergiinzt. Dieser erste Band enthillt fotomechanische Nachdrucke von vier Beitragen der Mathe- matiker C. F. GAUSS, B. RIEMANN und H. MINKOWSKI. Diese Arbeiten waren grund- legend filr die Entwicklung und Weiterentwicklung der Differentialgeometrie als innere Geometrie bis zur allgemeinen Rel, ativitatstheorie. Es ist gewiB nicht nur ein Zufall, daB sich filr diese drei Manner die produktive Zeit des Wirkens auf dem genannten Gebiet der Geometrie in der Universitiitsstadt Gottingen vollzog. Durch die folgenden Satze ALBERT EINSTEINS aus seiner Abhandlung tiber die Grund- ztige der Relativitatstheorie aus dem Jahre 1922 lassen sich in einfacher und klarer Weise die diesbeztiglichen Verdienste dieser drei Mathematiker charakterisieren: "GAUSS hat in seiner Fliichentheorie die metrischen Eigenschaften einer in einem dreidimensionalen euklidischen Raum eingebetteten Fliiche untersucht und gezeigt, daB diese durch Begriffe beschrieben werden konnen, die sich nur auf die Flache selbst, nicht aber auf die Ein- bettung beziehen . . . RIEMANN dehnte den GauBschen Gedankengang auf Kontinua beliebiger Dimensionszahl aus; er hat die physikalische Bedeutung dieser Verallgemei- nerung der Geometrie EUKLIDS mit prophetischem Blick vorausgesehen . . . Durch die Einfilhrung der imaginiiren Zeitvariable X4 = it hat MINKOWSKI die Invariantentheorie des vierdimensionalen Kontinuums des physikalischen Geschehens der des dreidimen- sionalen Kontinuums des euklidischen Raumes vollig analog gemacht.

The present volume contains all but two of the papers read at the conference, as well as a few papers and short notes submitted afterwards. We hope that it reflects faithfully the present state of research in the fields covered, and that it may provide an access to these fields for future investigations.

Differential Geometry in Physics is a treatment of the mathematical foundations of the theory of general relativity and gauge theory of quantum fields. The material is intended to help bridge the gap that often exists between theoretical physics and applied mathematics. The approach is to carve an optimal path to learning this challenging field by appealing to the much more accessible theory of curves and surfaces. The transition from classical differential geometry as developed by Gauss, Riemann and other giants, to the modern approach, is facilitated by a very intuitive approach that sacrifices some mathematical rigor for the sake of understanding the physics. The book features numerous examples of beautiful curves and surfaces often reflected in nature, plus more advanced computations of trajectory of particles in black holes. Also embedded in the later chapters is a detailed description of the famous Dirac monopole and instantons. Features of this book: * Chapters 1-4 and chapter 5 comprise the content of a one-semester course taught by the author for many years. * The material in the other chapters has served as the foundation for many master's thesis at University of North Carolina Wilmington for students seeking doctoral degrees. * An open access ebook edition is available at Open UNC (https://openunc.org) * The book contains over 80 illustrations, including a large array of surfaces related to the theory of soliton waves that does not commonly appear in standard mathematical texts on differential geometry.

This book collects papers presented in the Invited Workshop, "Liutex and Third Generation of Vortex Definition and Identification for Turbulence," from CHAOS2020, June 9-12, 2020, which was held online as a virtual conference. Liutex is a new physical quantity introduced by Prof. Chaoqun Liu of the University of Texas at Arlington. It is a vector and could give a unique and accurate mathematical definition for fluid rotation or vortex. The papers in this volume include some Liutex theories and many applications in hydrodynamics, aerodynamics and thermal dynamics including turbine machinery. As vortex exists everywhere in the universe, a mathematical definition of vortex or Liutex will play a critical role in scientific research. There is almost no place without vortex in fluid dynamics. As a projection, the Liutex theory will play an important role on the investigations of the vortex dynamics in hydrodynamics, aerodynamics, thermodynamics, oceanography, meteorology, metallurgy, civil engineering, astronomy, biology, etc. and to the researches of the generation, sustenance, modelling and controlling of turbulence.

Aus dem Vorwort: "Globale Probleme der Differentialgeometrie erfreuen sich eines immer noch wachsenden Interesses. Gerade in der Riemannschen Geometrie hat die Frage nach Beziehungen zwischen Riemannscher und topologischer Struktur in neuerer Zeit zu vielen schonen und uberraschenden Einsichten gefuhrt. Dabei denken wir hier vor allem an den Problemkreis: Welche topologischen Invarianten werden charakterisiert durch eine der wichtigsten isometrischen Invarianten, die Krummung? Ziel der folgenden Noten ist, einige zentrale Resultate in dieser Richtung darzustellen.... Wir haben uns bemuht, die Darstellung moglichst elementar und in sich abgeschlossen zu halten und einen einfachen leistungsfahigen Kalkul zu entwickeln.""

1. Innere Produkte Wir fUhren im Ramne ein kartesisches Koordinatensystem ein, dessen Achsen so orientiert sind, wie das in der Fig. 1 angedeutet ist. Die drei Koordinaten eines Punktes bezeichnen wir mit XI, X, x - Alle betrach- 2 3 teten Punkte setzen wir, falls nicht ausdrucklich etwas anderes gesagt wird, als reell voraus. Xz Xl Fig.1. Zwei in bestimmter Reihenfolge angeordnete Punkte und t) des Raumes mit den Koordinaten XI' X, x3 und YI' Y2, Y3 bestimmen eine 2 von nach t) fuhrende gerichtete Strecke. Zwei zu den Punktepaaren, t) und i, gehOrende gerichtete Strecken sind dann und nur dann gleichsinnig parallel und gleich lang, wenn die entsprechenden Koordi- natendifferenzen alle ubereinstimmen: (1) Yi - Xi = Yi - Xi (i = 1, 2, 3). Wir bezeichnen das System aller von den samtlichen Punkten des Rau- mes auslaufenden gerichteten Strecken von einer und derselben Rich- tung, demselben Sinn und der gleichen Lange als einen Vektor. Da fUr diese Strecken die Koordinatendifferenzen der beiden Endpunkte immer die gleichen sind, k6nnen wir diese drei Differenzen dem Vektor als seine 2 Einleitung Komponenten zuordnen, und zwar entsprechen die verschiedenen Systeme der als Vektorkomponenten genommenen Zahlentripel eineindeutig den verschiedenen Vektoren. An den Vektoren ist bemerkenswert, daB ihre Komponenten sich bei einer Parallelverschiebung des Koordinaten- systems nicht andern im Gegensatz zu den Koordinaten der Punkte.

This text focuses on developing an intimate acquaintance with the geometric meaning of curvature and thereby introduces and demonstrates all the main technical tools needed for a more advanced course on Riemannian manifolds. It covers proving the four most fundamental theorems relating curvature and topology: the Gauss-Bonnet Theorem, the Cartan-Hadamard Theorem, Bonnet's Theorem, and a special case of the Cartan-Ambrose-Hicks Theorem.

Discrete Differential Geometry (DDG) is an emerging discipline at the boundary between mathematics and computer science. It aims to translate concepts from classical differential geometry into a language that is purely finite and discrete, and can hence be used by algorithms to reason about geometric data. In contrast to standard numerical approximation, the central philosophy of DDG is to faithfully and exactly preserve key invariants of geometric objects at the discrete level. This process of translation from smooth to discrete helps to both illuminate the fundamental meaning behind geometric ideas and provide useful algorithmic guarantees. This volume is based on lectures delivered at the 2018 AMS Short Course ``Discrete Differential Geometry,'' held January 8-9, 2018, in San Diego, California. The papers in this volume illustrate the principles of DDG via several recent topics: discrete nets, discrete differential operators, discrete mappings, discrete conformal geometry, and discrete optimal transport.

A sequel to Lectures on Riemann Surfaces (Mathematical Notes, 1966), this volume continues the discussion of the dimensions of spaces of holomorphic cross-sections of complex line bundles over compact Riemann surfaces. Whereas the earlier treatment was limited to results obtainable chiefly by one-dimensional methods, the more detailed analysis presented here requires the use of various properties of Jacobi varieties and of symmetric products of Riemann surfaces, and so serves as a further introduction to these topics as well. The first chapter consists of a rather explicit description of a canonical basis for the Abelian differentials on a marked Riemann surface, and of the description of the canonical meromorphic differentials and the prime function of a marked Riemann surface. Chapter 2 treats Jacobi varieties of compact Riemann surfaces and various subvarieties that arise in determining the dimensions of spaces of holomorphic cross-sections of complex line bundles. In Chapter 3, the author discusses the relations between Jacobi varieties and symmetric products of Riemann surfaces relevant to the determination of dimensions of spaces of holomorphic cross-sections of complex line bundles. The final chapter derives Torelli's theorem following A. Weil, but in an analytical context. Originally published in 1973. The Princeton Legacy Library uses the latest print-on-demand technology to again make available previously out-of-print books from the distinguished backlist of Princeton University Press. These editions preserve the original texts of these important books while presenting them in durable paperback and hardcover editions. The goal of the Princeton Legacy Library is to vastly increase access to the rich scholarly heritage found in the thousands of books published by Princeton University Press since its founding in 1905.

Noncommutative geometry combines themes from algebra, analysis and geometry and has significant applications to physics. This book focuses on cyclic theory, and is based upon the lecture courses by Daniel G. Quillen at the University of Oxford from 1988-92, which developed his own approach to the subject. The basic definitions, examples and exercises provided here allow non-specialists and students with a background in elementary functional analysis, commutative algebra and differential geometry to get to grips with the subject. Quillen's development of cyclic theory emphasizes analogies between commutative and noncommutative theories, in which he reinterpreted classical results of Hamiltonian mechanics, operator algebras and differential graded algebras into a new formalism. In this book, cyclic theory is developed from motivating examples and background towards general results. Themes covered are relevant to current research, including homomorphisms modulo powers of ideals, traces on noncommutative differential forms, quasi-free algebras and Chern characters on connections.

Dieser Buchtitel ist Teil des Digitalisierungsprojekts Springer Book Archives mit Publikationen, die seit den Anfangen des Verlags von 1842 erschienen sind. Der Verlag stellt mit diesem Archiv Quellen fur die historische wie auch die disziplingeschichtliche Forschung zur Verfugung, die jeweils im historischen Kontext betrachtet werden mussen. Dieser Titel erschien in der Zeit vor 1945 und wird daher in seiner zeittypischen politisch-ideologischen Ausrichtung vom Verlag nicht beworben.