Classification of Actions of Discrete Kac Algebras on Injective Factors

Classification of Actions of Discrete Kac Algebras on Injective Factors

Author: Toshihiko Masuda

Publisher:

Published: 2017

Total Pages: 118

ISBN-13: 9781470436094

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Book Synopsis Classification of Actions of Discrete Kac Algebras on Injective Factors by : Toshihiko Masuda

Download or read book Classification of Actions of Discrete Kac Algebras on Injective Factors written by Toshihiko Masuda and published by . This book was released on 2017 with total page 118 pages. Available in PDF, EPUB and Kindle. Book excerpt:


Classification of Actions of Discrete Kac Algebras on Injective Factors

Classification of Actions of Discrete Kac Algebras on Injective Factors

Author: Toshihiko Masuda

Publisher: American Mathematical Soc.

Published: 2017-01-18

Total Pages: 134

ISBN-13: 1470420554

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The authors study two kinds of actions of a discrete amenable Kac algebra. The first one is an action whose modular part is normal. They construct a new invariant which generalizes a characteristic invariant for a discrete group action, and we will present a complete classification. The second is a centrally free action. By constructing a Rohlin tower in an asymptotic centralizer, the authors show that the Connes–Takesaki module is a complete invariant.


Book Synopsis Classification of Actions of Discrete Kac Algebras on Injective Factors by : Toshihiko Masuda

Download or read book Classification of Actions of Discrete Kac Algebras on Injective Factors written by Toshihiko Masuda and published by American Mathematical Soc.. This book was released on 2017-01-18 with total page 134 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors study two kinds of actions of a discrete amenable Kac algebra. The first one is an action whose modular part is normal. They construct a new invariant which generalizes a characteristic invariant for a discrete group action, and we will present a complete classification. The second is a centrally free action. By constructing a Rohlin tower in an asymptotic centralizer, the authors show that the Connes–Takesaki module is a complete invariant.


Rohlin Flows on von Neumann Algebras

Rohlin Flows on von Neumann Algebras

Author: Toshihiko Masuda

Publisher: American Mathematical Soc.

Published: 2016-10-05

Total Pages: 128

ISBN-13: 1470420163

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The authors will classify Rohlin flows on von Neumann algebras up to strong cocycle conjugacy. This result provides alternative approaches to some preceding results such as Kawahigashi's classification of flows on the injective type II1 factor, the classification of injective type III factors due to Connes, Krieger and Haagerup and the non-fullness of type III0 factors. Several concrete examples are also studied.


Book Synopsis Rohlin Flows on von Neumann Algebras by : Toshihiko Masuda

Download or read book Rohlin Flows on von Neumann Algebras written by Toshihiko Masuda and published by American Mathematical Soc.. This book was released on 2016-10-05 with total page 128 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors will classify Rohlin flows on von Neumann algebras up to strong cocycle conjugacy. This result provides alternative approaches to some preceding results such as Kawahigashi's classification of flows on the injective type II1 factor, the classification of injective type III factors due to Connes, Krieger and Haagerup and the non-fullness of type III0 factors. Several concrete examples are also studied.


Author:

Publisher: World Scientific

Published:

Total Pages: 1001

ISBN-13:

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Book Synopsis by :

Download or read book written by and published by World Scientific. This book was released on with total page 1001 pages. Available in PDF, EPUB and Kindle. Book excerpt:


Kac Algebras Arising from Composition of Subfactors: General Theory and Classification

Kac Algebras Arising from Composition of Subfactors: General Theory and Classification

Author: Masaki Izumi

Publisher: American Mathematical Soc.

Published: 2002

Total Pages: 215

ISBN-13: 0821829351

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This title deals with a map $\alpha$ from a finite group $G$ into the automorphism group $Aut({\mathcal L})$ of a factor ${\mathcal L}$ satisfying (i) $G=N \rtimes H$ is a semi-direct product, (ii) the induced map $g \in G \to [\alpha_g] \in Out({\mathcal L})=Aut({\mathcal L})/Int({\mathcal L})$ is an injective homomorphism, and (iii) the restrictions $\alpha \! \! \mid_N, \alpha \! \! \mid_H$ are genuine actions of the subgroups on the factor ${\mathcal L}$. The pair ${\mathcal M}={\mathcal L} \rtimes_{\alpha} H \supseteq {\mathcal N}={\mathcal L} DEGREES{\alpha\mid_N}$ (of the crossed product ${\mathcal L} \rtimes_{\alpha} H$ and the fixed-point algebra ${\mathcal L} DEGREES{\alpha\mid_N}$) gives an irreducible inclusion of factors with Jones index $\# G$. The inclusion ${\mathcal M} \supseteq {\mathcal N}$ is of depth $2$ and hence known to correspond to a Kac algebra of dim


Book Synopsis Kac Algebras Arising from Composition of Subfactors: General Theory and Classification by : Masaki Izumi

Download or read book Kac Algebras Arising from Composition of Subfactors: General Theory and Classification written by Masaki Izumi and published by American Mathematical Soc.. This book was released on 2002 with total page 215 pages. Available in PDF, EPUB and Kindle. Book excerpt: This title deals with a map $\alpha$ from a finite group $G$ into the automorphism group $Aut({\mathcal L})$ of a factor ${\mathcal L}$ satisfying (i) $G=N \rtimes H$ is a semi-direct product, (ii) the induced map $g \in G \to [\alpha_g] \in Out({\mathcal L})=Aut({\mathcal L})/Int({\mathcal L})$ is an injective homomorphism, and (iii) the restrictions $\alpha \! \! \mid_N, \alpha \! \! \mid_H$ are genuine actions of the subgroups on the factor ${\mathcal L}$. The pair ${\mathcal M}={\mathcal L} \rtimes_{\alpha} H \supseteq {\mathcal N}={\mathcal L} DEGREES{\alpha\mid_N}$ (of the crossed product ${\mathcal L} \rtimes_{\alpha} H$ and the fixed-point algebra ${\mathcal L} DEGREES{\alpha\mid_N}$) gives an irreducible inclusion of factors with Jones index $\# G$. The inclusion ${\mathcal M} \supseteq {\mathcal N}$ is of depth $2$ and hence known to correspond to a Kac algebra of dim


Hypercontractivity in Group von Neumann Algebras

Hypercontractivity in Group von Neumann Algebras

Author: Marius Junge

Publisher: American Mathematical Soc.

Published: 2017-09-25

Total Pages: 102

ISBN-13: 1470425653

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In this paper, the authors provide a combinatorial/numerical method to establish new hypercontractivity estimates in group von Neumann algebras. They illustrate their method with free groups, triangular groups and finite cyclic groups, for which they obtain optimal time hypercontractive inequalities with respect to the Markov process given by the word length and with an even integer. Interpolation and differentiation also yield general hypercontrativity for via logarithmic Sobolev inequalities. The authors' method admits further applications to other discrete groups without small loops as far as the numerical part—which varies from one group to another—is implemented and tested on a computer. The authors also develop another combinatorial method which does not rely on computational estimates and provides (non-optimal) hypercontractive inequalities for a larger class of groups/lengths, including any finitely generated group equipped with a conditionally negative word length, like infinite Coxeter groups. The authors' second method also yields hypercontractivity bounds for groups admitting a finite dimensional proper cocycle. Hypercontractivity fails for conditionally negative lengths in groups satisfying Kazhdan's property (T).


Book Synopsis Hypercontractivity in Group von Neumann Algebras by : Marius Junge

Download or read book Hypercontractivity in Group von Neumann Algebras written by Marius Junge and published by American Mathematical Soc.. This book was released on 2017-09-25 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper, the authors provide a combinatorial/numerical method to establish new hypercontractivity estimates in group von Neumann algebras. They illustrate their method with free groups, triangular groups and finite cyclic groups, for which they obtain optimal time hypercontractive inequalities with respect to the Markov process given by the word length and with an even integer. Interpolation and differentiation also yield general hypercontrativity for via logarithmic Sobolev inequalities. The authors' method admits further applications to other discrete groups without small loops as far as the numerical part—which varies from one group to another—is implemented and tested on a computer. The authors also develop another combinatorial method which does not rely on computational estimates and provides (non-optimal) hypercontractive inequalities for a larger class of groups/lengths, including any finitely generated group equipped with a conditionally negative word length, like infinite Coxeter groups. The authors' second method also yields hypercontractivity bounds for groups admitting a finite dimensional proper cocycle. Hypercontractivity fails for conditionally negative lengths in groups satisfying Kazhdan's property (T).


Knot Invariants and Higher Representation Theory

Knot Invariants and Higher Representation Theory

Author: Ben Webster

Publisher: American Mathematical Soc.

Published: 2018-01-16

Total Pages: 141

ISBN-13: 1470426501

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The author constructs knot invariants categorifying the quantum knot variants for all representations of quantum groups. He shows that these invariants coincide with previous invariants defined by Khovanov for sl and sl and by Mazorchuk-Stroppel and Sussan for sl . The author's technique is to study 2-representations of 2-quantum groups (in the sense of Rouquier and Khovanov-Lauda) categorifying tensor products of irreducible representations. These are the representation categories of certain finite dimensional algebras with an explicit diagrammatic presentation, generalizing the cyclotomic quotient of the KLR algebra. When the Lie algebra under consideration is sl , the author shows that these categories agree with certain subcategories of parabolic category for gl .


Book Synopsis Knot Invariants and Higher Representation Theory by : Ben Webster

Download or read book Knot Invariants and Higher Representation Theory written by Ben Webster and published by American Mathematical Soc.. This book was released on 2018-01-16 with total page 141 pages. Available in PDF, EPUB and Kindle. Book excerpt: The author constructs knot invariants categorifying the quantum knot variants for all representations of quantum groups. He shows that these invariants coincide with previous invariants defined by Khovanov for sl and sl and by Mazorchuk-Stroppel and Sussan for sl . The author's technique is to study 2-representations of 2-quantum groups (in the sense of Rouquier and Khovanov-Lauda) categorifying tensor products of irreducible representations. These are the representation categories of certain finite dimensional algebras with an explicit diagrammatic presentation, generalizing the cyclotomic quotient of the KLR algebra. When the Lie algebra under consideration is sl , the author shows that these categories agree with certain subcategories of parabolic category for gl .


Property ($T$) for Groups Graded by Root Systems

Property ($T$) for Groups Graded by Root Systems

Author: Mikhail Ershov

Publisher: American Mathematical Soc.

Published: 2017-09-25

Total Pages: 148

ISBN-13: 1470426048

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The 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.


Book Synopsis Property ($T$) for Groups Graded by Root Systems by : Mikhail Ershov

Download or read book Property ($T$) for Groups Graded by Root Systems written by Mikhail Ershov and published by American Mathematical Soc.. This book was released on 2017-09-25 with total page 148 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 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.


Orthogonal and Symplectic -level Densities

Orthogonal and Symplectic -level Densities

Author: A. M. Mason

Publisher: American Mathematical Soc.

Published: 2018-02-23

Total Pages: 93

ISBN-13: 1470426854

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In this paper the authors apply to the zeros of families of -functions with orthogonal or symplectic symmetry the method that Conrey and Snaith (Correlations of eigenvalues and Riemann zeros, 2008) used to calculate the -correlation of the zeros of the Riemann zeta function. This method uses the Ratios Conjectures (Conrey, Farmer, and Zimbauer, 2008) for averages of ratios of zeta or -functions. Katz and Sarnak (Zeroes of zeta functions and symmetry, 1999) conjecture that the zero statistics of families of -functions have an underlying symmetry relating to one of the classical compact groups , and . Here the authors complete the work already done with (Conrey and Snaith, Correlations of eigenvalues and Riemann zeros, 2008) to show how new methods for calculating the -level densities of eigenangles of random orthogonal or symplectic matrices can be used to create explicit conjectures for the -level densities of zeros of -functions with orthogonal or symplectic symmetry, including all the lower order terms. They show how the method used here results in formulae that are easily modified when the test function used has a restricted range of support, and this will facilitate comparison with rigorous number theoretic -level density results.


Book Synopsis Orthogonal and Symplectic -level Densities by : A. M. Mason

Download or read book Orthogonal and Symplectic -level Densities written by A. M. Mason and published by American Mathematical Soc.. This book was released on 2018-02-23 with total page 93 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this paper the authors apply to the zeros of families of -functions with orthogonal or symplectic symmetry the method that Conrey and Snaith (Correlations of eigenvalues and Riemann zeros, 2008) used to calculate the -correlation of the zeros of the Riemann zeta function. This method uses the Ratios Conjectures (Conrey, Farmer, and Zimbauer, 2008) for averages of ratios of zeta or -functions. Katz and Sarnak (Zeroes of zeta functions and symmetry, 1999) conjecture that the zero statistics of families of -functions have an underlying symmetry relating to one of the classical compact groups , and . Here the authors complete the work already done with (Conrey and Snaith, Correlations of eigenvalues and Riemann zeros, 2008) to show how new methods for calculating the -level densities of eigenangles of random orthogonal or symplectic matrices can be used to create explicit conjectures for the -level densities of zeros of -functions with orthogonal or symplectic symmetry, including all the lower order terms. They show how the method used here results in formulae that are easily modified when the test function used has a restricted range of support, and this will facilitate comparison with rigorous number theoretic -level density results.


Fundamental Solutions and Local Solvability for Nonsmooth Hormander's Operators

Fundamental Solutions and Local Solvability for Nonsmooth Hormander's Operators

Author: Marco Bramanti

Publisher: American Mathematical Soc.

Published: 2017-09-25

Total Pages: 92

ISBN-13: 1470425599

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The authors consider operators of the form in a bounded domain of where are nonsmooth Hörmander's vector fields of step such that the highest order commutators are only Hölder continuous. Applying Levi's parametrix method the authors construct a local fundamental solution for and provide growth estimates for and its first derivatives with respect to the vector fields. Requiring the existence of one more derivative of the coefficients the authors prove that also possesses second derivatives, and they deduce the local solvability of , constructing, by means of , a solution to with Hölder continuous . The authors also prove estimates on this solution.


Book Synopsis Fundamental Solutions and Local Solvability for Nonsmooth Hormander's Operators by : Marco Bramanti

Download or read book Fundamental Solutions and Local Solvability for Nonsmooth Hormander's Operators written by Marco Bramanti and published by American Mathematical Soc.. This book was released on 2017-09-25 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt: The authors consider operators of the form in a bounded domain of where are nonsmooth Hörmander's vector fields of step such that the highest order commutators are only Hölder continuous. Applying Levi's parametrix method the authors construct a local fundamental solution for and provide growth estimates for and its first derivatives with respect to the vector fields. Requiring the existence of one more derivative of the coefficients the authors prove that also possesses second derivatives, and they deduce the local solvability of , constructing, by means of , a solution to with Hölder continuous . The authors also prove estimates on this solution.