Bounded Cohomology of Discrete Groups

Bounded Cohomology of Discrete Groups PDF

Author: Roberto Frigerio

Publisher: American Mathematical Soc.

Published: 2017-11-21

Total Pages: 193

ISBN-13: 1470441462

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The theory of bounded cohomology, introduced by Gromov in the late 1980s, has had powerful applications in geometric group theory and the geometry and topology of manifolds, and has been the topic of active research continuing to this day. This monograph provides a unified, self-contained introduction to the theory and its applications, making it accessible to a student who has completed a first course in algebraic topology and manifold theory. The book can be used as a source for research projects for master's students, as a thorough introduction to the field for graduate students, and as a valuable landmark text for researchers, providing both the details of the theory of bounded cohomology and links of the theory to other closely related areas. The first part of the book is devoted to settling the fundamental definitions of the theory, and to proving some of the (by now classical) results on low-dimensional bounded cohomology and on bounded cohomology of topological spaces. The second part describes applications of the theory to the study of the simplicial volume of manifolds, to the classification of circle actions, to the analysis of maximal representations of surface groups, and to the study of flat vector bundles with a particular emphasis on the possible use of bounded cohomology in relation with the Chern conjecture. Each chapter ends with a discussion of further reading that puts the presented results in a broader context.

Continuous Bounded Cohomology of Locally Compact Groups

Continuous Bounded Cohomology of Locally Compact Groups PDF

Author: Nicolas Monod

Publisher: Springer

Published: 2003-07-01

Total Pages: 220

ISBN-13: 3540449620

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Recent research has repeatedly led to connections between important rigidity questions and bounded cohomology. However, the latter has remained by and large intractable. This monograph introduces the functorial study of the continuous bounded cohomology for topological groups, with coefficients in Banach modules. The powerful techniques of this more general theory have successfully solved a number of the original problems in bounded cohomology. As applications, one obtains, in particular, rigidity results for actions on the circle, for representations on complex hyperbolic spaces and on Teichmüller spaces. A special effort has been made to provide detailed proofs or references in quite some generality.

Bounded Cohomology and Simplicial Volume

Bounded Cohomology and Simplicial Volume PDF

Author: Caterina Campagnolo

Publisher: Cambridge University Press

Published: 2022-11-30

Total Pages: 171

ISBN-13: 100918329X

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An overview of bounded cohomology and simplicial volume covering the basics of the subject and recent research directions.

Discrete Groups and Geometric Structures

Discrete Groups and Geometric Structures PDF

Author: Karel Dekimpe

Publisher: American Mathematical Soc.

Published: 2009-11-12

Total Pages: 162

ISBN-13: 0821846477

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This volume reports on research related to Discrete Groups and Geometric Structures, as presented during the International Workshop held May 26-30, 2008, in Kortrijk, Belgium. Readers will benefit from impressive survey papers by John R. Parker on methods to construct and study lattices in complex hyperbolic space and by Ursula Hamenstadt on properties of group actions with a rank-one element on proper $\mathrm{CAT}(0)$-spaces. This volume also contains research papers in the area of group actions and geometric structures, including work on loops on a twice punctured torus, the simplicial volume of products and fiber bundles, the homology of Hantzsche-Wendt groups, rigidity of real Bott towers, circles in groups of smooth circle homeomorphisms, and groups generated by spine reflections admitting crooked fundamental domains.

On the Algebraic Foundations of Bounded Cohomology

On the Algebraic Foundations of Bounded Cohomology PDF

Author: Theo Bühler

Publisher: American Mathematical Soc.

Published: 2011

Total Pages: 126

ISBN-13: 0821853112

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It is a widespread opinion among experts that (continuous) bounded cohomology cannot be interpreted as a derived functor and that triangulated methods break down. The author proves that this is wrong. He uses the formalism of exact categories and their derived categories in order to construct a classical derived functor on the category of Banach $G$-modules with values in Waelbroeck's abelian category. This gives us an axiomatic characterization of this theory for free, and it is a simple matter to reconstruct the classical semi-normed cohomology spaces out of Waelbroeck's category. The author proves that the derived categories of right bounded and of left bounded complexes of Banach $G$-modules are equivalent to the derived category of two abelian categories (one for each boundedness condition), a consequence of the theory of abstract truncation and hearts of $t$-structures. Moreover, he proves that the derived categories of Banach $G$-modules can be constructed as the homotopy categories of model structures on the categories of chain complexes of Banach $G$-modules, thus proving that the theory fits into yet another standard framework of homological and homotopical algebra.

Discrete Geometric Analysis

Discrete Geometric Analysis PDF

Author: Motoko Kotani

Publisher: American Mathematical Soc.

Published: 2004

Total Pages: 274

ISBN-13: 0821833510

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This book is a collection of papers from the proceedings of the first symposium of the Japan Association for Mathematical Sciences. Topics covered center around problems of geometric analysis in relation to heat kernels, random walks, and Poisson boundaries on discrete groups, graphs, and other combinatorial objects. The material is suitable for graduate students and research mathematicians interested in heat kernels and random works on groups and graphs.

Flexibility of Group Actions on the Circle

Flexibility of Group Actions on the Circle PDF

Author: Sang-hyun Kim

Publisher: Springer

Published: 2019-01-02

Total Pages: 136

ISBN-13: 3030028550

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In this partly expository work, a framework is developed for building exotic circle actions of certain classical groups. The authors give general combination theorems for indiscrete isometry groups of hyperbolic space which apply to Fuchsian and limit groups. An abundance of integer-valued subadditive defect-one quasimorphisms on these groups follow as a corollary. The main classes of groups considered are limit and Fuchsian groups. Limit groups are shown to admit large collections of faithful actions on the circle with disjoint rotation spectra. For Fuchsian groups, further flexibility results are proved and the existence of non-geometric actions of free and surface groups is established. An account is given of the extant notions of semi-conjugacy, showing they are equivalent. This book is suitable for experts interested in flexibility of representations, and for non-experts wanting an introduction to group representations into circle homeomorphism groups.