Geometric Representation Theory and Extended Affine Lie Algebras

Download Geometric Representation Theory and Extended Affine Lie Algebras PDF Online Free

Author :
Publisher : American Mathematical Soc.
ISBN 13 : 082185237X
Total Pages : 226 pages
Book Rating : 4.8/5 (218 download)

DOWNLOAD NOW!


Book Synopsis Geometric Representation Theory and Extended Affine Lie Algebras by : Erhard Neher

Download or read book Geometric Representation Theory and Extended Affine Lie Algebras written by Erhard Neher and published by American Mathematical Soc.. This book was released on 2011 with total page 226 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lie theory has connections to many other disciplines such as geometry, number theory, mathematical physics, and algebraic combinatorics. The interaction between algebra, geometry and combinatorics has proven to be extremely powerful in shedding new light on each of these areas. This book presents the lectures given at the Fields Institute Summer School on Geometric Representation Theory and Extended Affine Lie Algebras held at the University of Ottawa in 2009. It provides a systematic account by experts of some of the exciting developments in Lie algebras and representation theory in the last two decades. It includes topics such as geometric realizations of irreducible representations in three different approaches, combinatorics and geometry of canonical and crystal bases, finite $W$-algebras arising as the quantization of the transversal slice to a nilpotent orbit, structure theory of extended affine Lie algebras, and representation theory of affine Lie algebras at level zero. This book will be of interest to mathematicians working in Lie algebras and to graduate students interested in learning the basic ideas of some very active research directions. The extensive references in the book will be helpful to guide non-experts to the original sources.

Geometric Representation Theory and Extended Affine Lie Algebras

Download Geometric Representation Theory and Extended Affine Lie Algebras PDF Online Free

Author :
Publisher : American Mathematical Soc.
ISBN 13 : 9780821871614
Total Pages : 213 pages
Book Rating : 4.8/5 (716 download)

DOWNLOAD NOW!


Book Synopsis Geometric Representation Theory and Extended Affine Lie Algebras by : Erhard Neher

Download or read book Geometric Representation Theory and Extended Affine Lie Algebras written by Erhard Neher and published by American Mathematical Soc.. This book was released on 2011 with total page 213 pages. Available in PDF, EPUB and Kindle. Book excerpt: This text presents lectures given at the Fields Institute Summer School on Geometric Representation Theory and Extended Affine Lie Algebras held at the University of Ottawa in 2009. It provides a systematic account by experts of some of the developments in Lie algebras and representation theory in the last two decades.

Lie Theory

Download Lie Theory PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 9780817633738
Total Pages : 348 pages
Book Rating : 4.6/5 (337 download)

DOWNLOAD NOW!


Book Synopsis Lie Theory by : Jean-Philippe Anker

Download or read book Lie Theory written by Jean-Philippe Anker and published by Springer Science & Business Media. This book was released on 2004 with total page 348 pages. Available in PDF, EPUB and Kindle. Book excerpt: * First of three independent, self-contained volumes under the general title, "Lie Theory," featuring original results and survey work from renowned mathematicians. * Contains J. C. Jantzen's "Nilpotent Orbits in Representation Theory," and K.-H. Neeb's "Infinite Dimensional Groups and their Representations." * Comprehensive treatments of the relevant geometry of orbits in Lie algebras, or their duals, and the correspondence to representations. * Should benefit graduate students and researchers in mathematics and mathematical physics.

Quantum Affine Algebras, Extended Affine Lie Algebras, and Their Applications

Download Quantum Affine Algebras, Extended Affine Lie Algebras, and Their Applications PDF Online Free

Author :
Publisher : American Mathematical Soc.
ISBN 13 : 0821858327
Total Pages : 314 pages
Book Rating : 4.8/5 (218 download)

DOWNLOAD NOW!


Book Synopsis Quantum Affine Algebras, Extended Affine Lie Algebras, and Their Applications by : Yun Gao, Naihuan Jing, Michael Lau, and Kailash C. Misra

Download or read book Quantum Affine Algebras, Extended Affine Lie Algebras, and Their Applications written by Yun Gao, Naihuan Jing, Michael Lau, and Kailash C. Misra and published by American Mathematical Soc.. This book was released on 2010 with total page 314 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Developments and Trends in Infinite-Dimensional Lie Theory

Download Developments and Trends in Infinite-Dimensional Lie Theory PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 0817647414
Total Pages : 492 pages
Book Rating : 4.8/5 (176 download)

DOWNLOAD NOW!


Book Synopsis Developments and Trends in Infinite-Dimensional Lie Theory by : Karl-Hermann Neeb

Download or read book Developments and Trends in Infinite-Dimensional Lie Theory written by Karl-Hermann Neeb and published by Springer Science & Business Media. This book was released on 2010-10-17 with total page 492 pages. Available in PDF, EPUB and Kindle. Book excerpt: This collection of invited expository articles focuses on recent developments and trends in infinite-dimensional Lie theory, which has become one of the core areas of modern mathematics. The book is divided into three parts: infinite-dimensional Lie (super-)algebras, geometry of infinite-dimensional Lie (transformation) groups, and representation theory of infinite-dimensional Lie groups. Contributors: B. Allison, D. Beltiţă, W. Bertram, J. Faulkner, Ph. Gille, H. Glöckner, K.-H. Neeb, E. Neher, I. Penkov, A. Pianzola, D. Pickrell, T.S. Ratiu, N.R. Scheithauer, C. Schweigert, V. Serganova, K. Styrkas, K. Waldorf, and J.A. Wolf.

Representation Theories and Algebraic Geometry

Download Representation Theories and Algebraic Geometry PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 9401591318
Total Pages : 455 pages
Book Rating : 4.4/5 (15 download)

DOWNLOAD NOW!


Book Synopsis Representation Theories and Algebraic Geometry by : A. Broer

Download or read book Representation Theories and Algebraic Geometry written by A. Broer and published by Springer Science & Business Media. This book was released on 2013-03-09 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 12 lectures presented in Representation Theories and Algebraic Geometry focus on the very rich and powerful interplay between algebraic geometry and the representation theories of various modern mathematical structures, such as reductive groups, quantum groups, Hecke algebras, restricted Lie algebras, and their companions. This interplay has been extensively exploited during recent years, resulting in great progress in these representation theories. Conversely, a great stimulus has been given to the development of such geometric theories as D-modules, perverse sheafs and equivariant intersection cohomology. The range of topics covered is wide, from equivariant Chow groups, decomposition classes and Schubert varieties, multiplicity free actions, convolution algebras, standard monomial theory, and canonical bases, to annihilators of quantum Verma modules, modular representation theory of Lie algebras and combinatorics of representation categories of Harish-Chandra modules.

Introduction to Finite and Infinite Dimensional Lie (Super)algebras

Download Introduction to Finite and Infinite Dimensional Lie (Super)algebras PDF Online Free

Author :
Publisher : Academic Press
ISBN 13 : 012804683X
Total Pages : 512 pages
Book Rating : 4.1/5 (28 download)

DOWNLOAD NOW!


Book Synopsis Introduction to Finite and Infinite Dimensional Lie (Super)algebras by : Neelacanta Sthanumoorthy

Download or read book Introduction to Finite and Infinite Dimensional Lie (Super)algebras written by Neelacanta Sthanumoorthy and published by Academic Press. This book was released on 2016-04-26 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Lie superalgebras are a natural generalization of Lie algebras, having applications in geometry, number theory, gauge field theory, and string theory. Introduction to Finite and Infinite Dimensional Lie Algebras and Superalgebras introduces the theory of Lie superalgebras, their algebras, and their representations. The material covered ranges from basic definitions of Lie groups to the classification of finite-dimensional representations of semi-simple Lie algebras. While discussing all classes of finite and infinite dimensional Lie algebras and Lie superalgebras in terms of their different classes of root systems, the book focuses on Kac-Moody algebras. With numerous exercises and worked examples, it is ideal for graduate courses on Lie groups and Lie algebras. Discusses the fundamental structure and all root relationships of Lie algebras and Lie superalgebras and their finite and infinite dimensional representation theory Closely describes BKM Lie superalgebras, their different classes of imaginary root systems, their complete classifications, root-supermultiplicities, and related combinatorial identities Includes numerous tables of the properties of individual Lie algebras and Lie superalgebras Focuses on Kac-Moody algebras

A Study in Derived Algebraic Geometry

Download A Study in Derived Algebraic Geometry PDF Online Free

Author :
Publisher : American Mathematical Society
ISBN 13 : 1470452855
Total Pages : 436 pages
Book Rating : 4.4/5 (74 download)

DOWNLOAD NOW!


Book Synopsis A Study in Derived Algebraic Geometry by : Dennis Gaitsgory

Download or read book A Study in Derived Algebraic Geometry written by Dennis Gaitsgory and published by American Mathematical Society. This book was released on 2020-10-07 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: Derived algebraic geometry is a far-reaching generalization of algebraic geometry. It has found numerous applications in other parts of mathematics, most prominently in representation theory. This volume develops deformation theory, Lie theory and the theory of algebroids in the context of derived algebraic geometry. To that end, it introduces the notion of inf-scheme, which is an infinitesimal deformation of a scheme and studies ind-coherent sheaves on such. As an application of the general theory, the six-functor formalism for D-modules in derived geometry is obtained. This volume consists of two parts. The first part introduces the notion of ind-scheme and extends the theory of ind-coherent sheaves to inf-schemes, obtaining the theory of D-modules as an application. The second part establishes the equivalence between formal Lie group(oids) and Lie algebr(oids) in the category of ind-coherent sheaves. This equivalence gives a vast generalization of the equivalence between Lie algebras and formal moduli problems. This theory is applied to study natural filtrations in formal derived geometry generalizing the Hodge filtration.

Combinatorial and Geometric Representation Theory

Download Combinatorial and Geometric Representation Theory PDF Online Free

Author :
Publisher : American Mathematical Soc.
ISBN 13 : 9780821856604
Total Pages : 204 pages
Book Rating : 4.8/5 (566 download)

DOWNLOAD NOW!


Book Synopsis Combinatorial and Geometric Representation Theory by : Seok-Jin Kang

Download or read book Combinatorial and Geometric Representation Theory written by Seok-Jin Kang and published by American Mathematical Soc.. This book was released on 2003 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume presents the proceedings of the international conference on Combinatorial and Geometric Representation Theory. In the field of representation theory, a wide variety of mathematical ideas are providing new insights, giving powerful methods for understanding the theory, and presenting various applications to other branches of mathematics. Over the past two decades, there have been remarkable developments. This book explains the strong connections between combinatorics, geometry, and representation theory. It is suitable for graduate students and researchers interested in representation theory.

Representation Theory and Complex Geometry

Download Representation Theory and Complex Geometry PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 0817649387
Total Pages : 506 pages
Book Rating : 4.8/5 (176 download)

DOWNLOAD NOW!


Book Synopsis Representation Theory and Complex Geometry by : Neil Chriss

Download or read book Representation Theory and Complex Geometry written by Neil Chriss and published by Springer Science & Business Media. This book was released on 2009-12-24 with total page 506 pages. Available in PDF, EPUB and Kindle. Book excerpt: "The book is largely self-contained...There is a nice introduction to symplectic geometry and a charming exposition of equivariant K-theory. Both are enlivened by examples related to groups...An attractive feature is the attempt to convey some informal ‘wisdom’ rather than only the precise definitions. As a number of results [are] due to the authors, one finds some of the original excitement. This is the only available introduction to geometric representation theory...it has already proved successful in introducing a new generation to the subject." (Bulletin of the AMS)

Basic Theory of Algebraic Groups and Lie Algebras

Download Basic Theory of Algebraic Groups and Lie Algebras PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 1461381142
Total Pages : 276 pages
Book Rating : 4.4/5 (613 download)

DOWNLOAD NOW!


Book Synopsis Basic Theory of Algebraic Groups and Lie Algebras by : G. P. Hochschild

Download or read book Basic Theory of Algebraic Groups and Lie Algebras written by G. P. Hochschild and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 276 pages. Available in PDF, EPUB and Kindle. Book excerpt: The theory of algebraic groups results from the interaction of various basic techniques from field theory, multilinear algebra, commutative ring theory, algebraic geometry and general algebraic representation theory of groups and Lie algebras. It is thus an ideally suitable framework for exhibiting basic algebra in action. To do that is the principal concern of this text. Accordingly, its emphasis is on developing the major general mathematical tools used for gaining control over algebraic groups, rather than on securing the final definitive results, such as the classification of the simple groups and their irreducible representations. In the same spirit, this exposition has been made entirely self-contained; no detailed knowledge beyond the usual standard material of the first one or two years of graduate study in algebra is pre supposed. The chapter headings should be sufficient indication of the content and organisation of this book. Each chapter begins with a brief announcement of its results and ends with a few notes ranging from supplementary results, amplifications of proofs, examples and counter-examples through exercises to references. The references are intended to be merely suggestions for supplementary reading or indications of original sources, especially in cases where these might not be the expected ones. Algebraic group theory has reached a state of maturity and perfection where it may no longer be necessary to re-iterate an account of its genesis. Of the material to be presented here, including much of the basic support, the major portion is due to Claude Chevalley.

Infinite Dimensional Lie Groups in Geometry and Representation Theory

Download Infinite Dimensional Lie Groups in Geometry and Representation Theory PDF Online Free

Author :
Publisher : World Scientific
ISBN 13 : 9814488143
Total Pages : 176 pages
Book Rating : 4.8/5 (144 download)

DOWNLOAD NOW!


Book Synopsis Infinite Dimensional Lie Groups in Geometry and Representation Theory by : Augustin Banyaga

Download or read book Infinite Dimensional Lie Groups in Geometry and Representation Theory written by Augustin Banyaga and published by World Scientific. This book was released on 2002-07-12 with total page 176 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book constitutes the proceedings of the 2000 Howard conference on “Infinite Dimensional Lie Groups in Geometry and Representation Theory”. It presents some important recent developments in this area. It opens with a topological characterization of regular groups, treats among other topics the integrability problem of various infinite dimensional Lie algebras, presents substantial contributions to important subjects in modern geometry, and concludes with interesting applications to representation theory. The book should be a new source of inspiration for advanced graduate students and established researchers in the field of geometry and its applications to mathematical physics. Contents:Inheritance Properties for Lipschitz-Metrizable Frölicher Groups (J Teichmann)Around the Exponential Mapping (T Robart)On a Solution to a Global Inverse Problem with Respect to Certain Generalized Symmetrizable Kac-Moody Algebras (J A Leslie)The Lie Group of Fourier Integral Operators on Open Manifolds (R Schmid)On Some Properties of Leibniz Algebroids (A Wade)On the Geometry of Locally Conformal Symplectic Manifolds (A Banyaga)Some Properties of Locally Conformal Symplectic Manifolds (S Haller)Criticality of Unit Contact Vector Fields (P Rukimbira)Orbifold Homeomorphism and Diffeomorphism Groups (J E Borzellino & V Brunsden)A Note on Isotopies of Symplectic and Poisson Structures (A Banyaga & P Donato)Remarks on Actions on Compacta by Some Infinite-Dimensional Groups (V Pestov) Readership: Graduate students and researchers in mathematics and mathematical physics. Keywords:

Geometry of Moduli Spaces and Representation Theory

Download Geometry of Moduli Spaces and Representation Theory PDF Online Free

Author :
Publisher : American Mathematical Soc.
ISBN 13 : 1470435748
Total Pages : 436 pages
Book Rating : 4.4/5 (74 download)

DOWNLOAD NOW!


Book Synopsis Geometry of Moduli Spaces and Representation Theory by : Roman Bezrukavnikov

Download or read book Geometry of Moduli Spaces and Representation Theory written by Roman Bezrukavnikov and published by American Mathematical Soc.. This book was released on 2017-12-15 with total page 436 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is based on lectures given at the Graduate Summer School of the 2015 Park City Mathematics Institute program “Geometry of moduli spaces and representation theory”, and is devoted to several interrelated topics in algebraic geometry, topology of algebraic varieties, and representation theory. Geometric representation theory is a young but fast developing research area at the intersection of these subjects. An early profound achievement was the famous conjecture by Kazhdan–Lusztig about characters of highest weight modules over a complex semi-simple Lie algebra, and its subsequent proof by Beilinson-Bernstein and Brylinski-Kashiwara. Two remarkable features of this proof have inspired much of subsequent development: intricate algebraic data turned out to be encoded in topological invariants of singular geometric spaces, while proving this fact required deep general theorems from algebraic geometry. Another focus of the program was enumerative algebraic geometry. Recent progress showed the role of Lie theoretic structures in problems such as calculation of quantum cohomology, K-theory, etc. Although the motivation and technical background of these constructions is quite different from that of geometric Langlands duality, both theories deal with topological invariants of moduli spaces of maps from a target of complex dimension one. Thus they are at least heuristically related, while several recent works indicate possible strong technical connections. The main goal of this collection of notes is to provide young researchers and experts alike with an introduction to these areas of active research and promote interaction between the two related directions.

Extended Affine Lie Algebras and Their Root Systems

Download Extended Affine Lie Algebras and Their Root Systems PDF Online Free

Author :
Publisher : American Mathematical Soc.
ISBN 13 : 0821805940
Total Pages : 122 pages
Book Rating : 4.8/5 (218 download)

DOWNLOAD NOW!


Book Synopsis Extended Affine Lie Algebras and Their Root Systems by : Bruce Normansell Allison

Download or read book Extended Affine Lie Algebras and Their Root Systems written by Bruce Normansell Allison and published by American Mathematical Soc.. This book was released on 1997 with total page 122 pages. Available in PDF, EPUB and Kindle. Book excerpt: This work is about extended affine Lie algebras (EALA's) and their root systems. EALA's were introduced by Hoegh-Krohn and Torresani under the name irreducible quasi-simple Lie algebras. The major objective is to develop enough theory to provide a firm foundation for further study of EALA's. The first chapter of the paper is devoted to establishing some basic structure theory. It includes a proof of the fact that, as conjectured by Kac, the invariant symmetric bilinear form on an EALA can be scaled so that its restriction to the real span of the root system is positive semi-definite. The second chapter studies extended affine root systems (EARS) which are an axiomatized version of the root systems arising from EALA's. The concept of a semilattice is used to give a complete description of EARS. In the final chapter, a number of new examples of extended affine Lie algebras are given. The concluding appendix contains an axiomatic characterization of the nonisotropic roots in an EARS in a more general context than the one used in the rest of the paper. Features: Provides a foundation for the study of an important class of Lie algebras that generalizes the class of affine Kac-Moody Lie algebras Includes material on Lie algebras and on root systems that can be read independently.

Categorification and Higher Representation Theory

Download Categorification and Higher Representation Theory PDF Online Free

Author :
Publisher : American Mathematical Soc.
ISBN 13 : 1470424606
Total Pages : 361 pages
Book Rating : 4.4/5 (74 download)

DOWNLOAD NOW!


Book Synopsis Categorification and Higher Representation Theory by : Anna Beliakova

Download or read book Categorification and Higher Representation Theory written by Anna Beliakova and published by American Mathematical Soc.. This book was released on 2017-02-21 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: The emergent mathematical philosophy of categorification is reshaping our view of modern mathematics by uncovering a hidden layer of structure in mathematics, revealing richer and more robust structures capable of describing more complex phenomena. Categorified representation theory, or higher representation theory, aims to understand a new level of structure present in representation theory. Rather than studying actions of algebras on vector spaces where algebra elements act by linear endomorphisms of the vector space, higher representation theory describes the structure present when algebras act on categories, with algebra elements acting by functors. The new level of structure in higher representation theory arises by studying the natural transformations between functors. This enhanced perspective brings into play a powerful new set of tools that deepens our understanding of traditional representation theory. This volume exhibits some of the current trends in higher representation theory and the diverse techniques that are being employed in this field with the aim of showcasing the many applications of higher representation theory. The companion volume (Contemporary Mathematics, Volume 684) is devoted to categorification in geometry, topology, and physics.

Infinite Dimensional Lie Algebras and Groups

Download Infinite Dimensional Lie Algebras and Groups PDF Online Free

Author :
Publisher : World Scientific
ISBN 13 : 9814663174
Total Pages : 640 pages
Book Rating : 4.8/5 (146 download)

DOWNLOAD NOW!


Book Synopsis Infinite Dimensional Lie Algebras and Groups by : V G Kac

Download or read book Infinite Dimensional Lie Algebras and Groups written by V G Kac and published by World Scientific. This book was released on 1989-07-01 with total page 640 pages. Available in PDF, EPUB and Kindle. Book excerpt: Contents:Integrable Representation of Kac-Moody Algebras: Results and Open Problems (V Chari & A Pressley)Existence of Certain Components in the Tensor Product of Two Integrable Highest Weight Modules for Kac-Moody Algebras (SKumar)Frobenius Action on the B-Cohomology (O Mathieu)Certain Rank Two Subsystems of Kac-Moody Root Systems (J Morita)Lie Groups Associated to Kac-Moody Lie Algebras: An Analytic Approach (E Rodriguez-Carrington)Almost Split-K-Forms of Kac-Moody Algebras (G Rousseau)Global Representations of the Diffeomorphism Groups of the Circle (F Bien)Path Space Realization of the Basic Representation of An(1) (E Date et al)Boson-Fermion Correspondence Over (C De Concini et al)Classification of Modular Invariant Representations of Affine Algebras (V G Kac & M Wakimoto)Standard Monomial Theory for SL2 (V Lakshmibai & C S Seshadri)Some Results on Modular Invariant Representations (S Lu)Current Algebras in 3+1 Space-Time Dimensions (J Mickelson)Standard Representations of An(1) (M Primc)Representations of the Algebra Uq(sI(2)), q-Orthogonal Polynomials and Invariants of Links (A N Kirillov & N Yu Reshetikhin)Infinite Super Grassmannians and Super Plücker Equations (M J Bergvelt)Drinfeld-Sokolov Hierarchies and t-Functions (H J Imbens)Super Boson-Fermion Correspondence of Type B (V G Kac & J W van de Leur)Prym Varieties and Soliton Equations (T Shiota)Polynomial Solutions of the BKP Hierarchy and Projective Representations of Symmetric Groups (Y You)Toward Generalized Macdonald's Identities (D Bernard)Conformal Theories with Non-Linearly Extended Virasoro Symmetries and Lie Algebra Classification (A Bilal & J-LGervais)Extended Conformal Algebras from Kac-Moody Algebras (P Bouwknegt)Meromorphic Conformal Field Theory (P Goddard)Local Extensions of the U(1) Current Algebra and Their Positive Energy Representations (R R Paunov & I T Todorov)Conformal Field Theory on Moduli Family of Stable Curves with Gauge Symmetries (A Tsuchiya & Y Yamada) Readership: Mathematicians and mathematical physicists

Geometry and Representation Theory of Real and p-adic groups

Download Geometry and Representation Theory of Real and p-adic groups PDF Online Free

Author :
Publisher : Springer Science & Business Media
ISBN 13 : 1461241626
Total Pages : 330 pages
Book Rating : 4.4/5 (612 download)

DOWNLOAD NOW!


Book Synopsis Geometry and Representation Theory of Real and p-adic groups by : Juan Tirao

Download or read book Geometry and Representation Theory of Real and p-adic groups written by Juan Tirao and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 330 pages. Available in PDF, EPUB and Kindle. Book excerpt: The representation theory of Lie groups plays a central role in both clas sical and recent developments in many parts of mathematics and physics. In August, 1995, the Fifth Workshop on Representation Theory of Lie Groups and its Applications took place at the Universidad Nacional de Cordoba in Argentina. Organized by Joseph Wolf, Nolan Wallach, Roberto Miatello, Juan Tirao, and Jorge Vargas, the workshop offered expository courses on current research, and individual lectures on more specialized topics. The present vol ume reflects the dual character of the workshop. Many of the articles will be accessible to graduate students and others entering the field. Here is a rough outline of the mathematical content. (The editors beg the indulgence of the readers for any lapses in this preface in the high standards of historical and mathematical accuracy that were imposed on the authors of the articles. ) Connections between flag varieties and representation theory for real re ductive groups have been studied for almost fifty years, from the work of Gelfand and Naimark on principal series representations to that of Beilinson and Bernstein on localization. The article of Wolf provides a detailed introduc tion to the analytic side of these developments. He describes the construction of standard tempered representations in terms of square-integrable partially harmonic forms (on certain real group orbits on a flag variety), and outlines the ingredients in the Plancherel formula. Finally, he describes recent work on the complex geometry of real group orbits on partial flag varieties.