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Author: Bekka M Bachir La Harpe Pierre de Valette Alain
Publisher:
Published: 2014-05-14
Total Pages: 488
ISBN-13: 9780511395116
DOWNLOAD EBOOKA comprehensive introduction to the role of Property (T), with applications to an amazing number of fields within mathematics.
Author: Pierre-Alain Cherix
Publisher: Birkhäuser
Published: 2012-12-06
Total Pages: 130
ISBN-13: 3034882378
DOWNLOAD EBOOKA locally compact group has the Haagerup property, or is a-T-menable in the sense of Gromov, if it admits a proper isometric action on some affine Hilbert space. As Gromov's pun is trying to indicate, this definition is designed as a strong negation to Kazhdan's property (T), characterized by the fact that every isometric action on some affine Hilbert space has a fixed point. This book is to covers various aspects of the Haagerup property. It gives several new examples.
Author: Alex Lubotzky
Publisher: Springer Science & Business Media
Published: 2010-02-17
Total Pages: 201
ISBN-13: 3034603320
DOWNLOAD EBOOKIn the last ?fteen years two seemingly unrelated problems, one in computer science and the other in measure theory, were solved by amazingly similar techniques from representation theory and from analytic number theory. One problem is the - plicit construction of expanding graphs («expanders»). These are highly connected sparse graphs whose existence can be easily demonstrated but whose explicit c- struction turns out to be a dif?cult task. Since expanders serve as basic building blocks for various distributed networks, an explicit construction is highly des- able. The other problem is one posed by Ruziewicz about seventy years ago and studied by Banach [Ba]. It asks whether the Lebesgue measure is the only ?nitely additive measure of total measure one, de?ned on the Lebesgue subsets of the n-dimensional sphere and invariant under all rotations. The two problems seem, at ?rst glance, totally unrelated. It is therefore so- what surprising that both problems were solved using similar methods: initially, Kazhdan’s property (T) from representation theory of semi-simple Lie groups was applied in both cases to achieve partial results, and later on, both problems were solved using the (proved) Ramanujan conjecture from the theory of automorphic forms. The fact that representation theory and automorphic forms have anything to do with these problems is a surprise and a hint as well that the two questions are strongly related.
Author: Armand Borel
Publisher: American Mathematical Soc.
Published: 2019-11-07
Total Pages: 133
ISBN-13: 1470452316
DOWNLOAD EBOOKFifty years after it made the transition from mimeographed lecture notes to a published book, Armand Borel's Introduction aux groupes arithmétiques continues to be very important for the theory of arithmetic groups. In particular, Chapter III of the book remains the standard reference for fundamental results on reduction theory, which is crucial in the study of discrete subgroups of Lie groups and the corresponding homogeneous spaces. The review of the original French version in Mathematical Reviews observes that “the style is concise and the proofs (in later sections) are often demanding of the reader.” To make the translation more approachable, numerous footnotes provide helpful comments.
Author: Terence Tao
Publisher: American Mathematical Soc.
Published: 2015-04-16
Total Pages: 319
ISBN-13: 1470421968
DOWNLOAD EBOOKExpander graphs are an important tool in theoretical computer science, geometric group theory, probability, and number theory. Furthermore, the techniques used to rigorously establish the expansion property of a graph draw from such diverse areas of mathematics as representation theory, algebraic geometry, and arithmetic combinatorics. This text focuses on the latter topic in the important case of Cayley graphs on finite groups of Lie type, developing tools such as Kazhdan's property (T), quasirandomness, product estimates, escape from subvarieties, and the Balog-Szemerédi-Gowers lemma. Applications to the affine sieve of Bourgain, Gamburd, and Sarnak are also given. The material is largely self-contained, with additional sections on the general theory of expanders, spectral theory, Lie theory, and the Lang-Weil bound, as well as numerous exercises and other optional material.
Author: Mikhail Ershov
Publisher: American Mathematical Soc.
Published: 2017-09-25
Total Pages: 148
ISBN-13: 1470426048
DOWNLOAD EBOOKThe authors introduce and study the class of groups graded by root systems. They prove that if is an irreducible classical root system of rank and is a group graded by , then under certain natural conditions on the grading, the union of the root subgroups is a Kazhdan subset of . As the main application of this theorem the authors prove that for any reduced irreducible classical root system of rank and a finitely generated commutative ring with , the Steinberg group and the elementary Chevalley group have property . They also show that there exists a group with property which maps onto all finite simple groups of Lie type and rank , thereby providing a “unified” proof of expansion in these groups.
Author: A. S. Kechris
Publisher: American Mathematical Soc.
Published: 2010
Total Pages: 258
ISBN-13: 0821848941
DOWNLOAD EBOOKA study of ergodic, measure preserving actions of countable discrete groups on standard probability spaces. It explores a direction that emphasizes a global point of view, concentrating on the structure of the space of measure preserving actions of a given group and its associated cocycle spaces.
Author: Andrés Navas
Publisher: University of Chicago Press
Published: 2011-06-30
Total Pages: 310
ISBN-13: 0226569519
DOWNLOAD EBOOKIn recent years scholars from a variety of branches of mathematics have made several significant developments in the theory of group actions. Groups of Circle Diffeomorphisms systematically explores group actions on the simplest closed manifold, the circle. As the group of circle diffeomorphisms is an important subject in modern mathematics, this book will be of interest to those doing research in group theory, dynamical systems, low dimensional geometry and topology, and foliation theory. The book is mostly self-contained and also includes numerous complementary exercises, making it an excellent textbook for undergraduate and graduate students.
Author: Oleg Bogopolski
Publisher: Springer Science & Business Media
Published: 2011-01-28
Total Pages: 318
ISBN-13: 3764399112
DOWNLOAD EBOOKThis volume assembles several research papers in all areas of geometric and combinatorial group theory originated in the recent conferences in Dortmund and Ottawa in 2007. It contains high quality refereed articles developing new aspects of these modern and active fields in mathematics. It is also appropriate to advanced students interested in recent results at a research level.
Author: James Haglund
Publisher: American Mathematical Soc.
Published: 2008
Total Pages: 178
ISBN-13: 0821844113
DOWNLOAD EBOOKThis work contains detailed descriptions of developments in the combinatorics of the space of diagonal harmonics, a topic at the forefront of current research in algebraic combinatorics. These developments have led in turn to some surprising discoveries in the combinatorics of Macdonald polynomials.
