Functional analysis | Operator theory | Representation theory

Uniformly bounded representation

In mathematics, a uniformly bounded representation of a locally compact group on a Hilbert space is a homomorphism into the bounded invertible operators which is continuous for the strong operator topology, and such that is finite. In 1947 Béla Szőkefalvi-Nagy established that any uniformly bounded representation of the integers or the real numbers is unitarizable, i.e. conjugate by an invertible operator to a unitary representation. For the integers this gives a criterion for an invertible operator to be similar to a unitary operator: the operator norms of all the positive and negative powers must be uniformly bounded. The result on unitarizability of uniformly bounded representations was extended in 1950 by Dixmier, Day and Nakamura-Takeda to all locally compact amenable groups, following essentially the method of proof of Sz-Nagy. The result is known to fail for non-amenable groups such as SL(2,R) and the free group on two generators. conjectured that a locally compact group is amenable if and only if every uniformly bounded representation is unitarizable. (Wikipedia).

Video thumbnail

Convergent sequences are bounded

Convergent Sequences are Bounded In this video, I show that if a sequence is convergent, then it must be bounded, that is some part of it doesn't go to infinity. This is an important result that is used over and over again in analysis. Enjoy! Other examples of limits can be seen in the

From playlist Sequences

Video thumbnail

Every Function with a Bounded Derivative is Uniformly Continuous Proof

In this video I prove that every function with a bounded derivative is uniformly continuous. I hope this video helps someone out there who is studying mathematical analysis/advanced calculus. If you enjoyed this video please consider liking, sharing, and subscribing. You can also help su

From playlist Advanced Calculus

Video thumbnail

The Sum of Uniformly Continuous Functions is Uniformly Continuous Proof

The Sum of Uniformly Continuous Functions is Uniformly Continuous Proof If you enjoyed this video please consider liking, sharing, and subscribing. You can also help support my channel by becoming a member https://www.youtube.com/channel/UCr7lmzIk63PZnBw3bezl-Mg/join Thank you:)

From playlist Advanced Calculus

Video thumbnail

Uniform Probability Distribution Examples

Overview and definition of a uniform probability distribution. Worked examples of how to find probabilities.

From playlist Probability Distributions

Video thumbnail

Math 131 092816 Continuity; Continuity and Compactness

Review definition of limit. Definition of continuity at a point; remark about isolated points; connection with limits. Composition of continuous functions. Alternate characterization of continuous functions (topological definition). Continuity and compactness: continuous image of a com

From playlist Course 7: (Rudin's) Principles of Mathematical Analysis

Video thumbnail

How to Prove a Function is Uniformly Continuous

Please Subscribe here, thank you!!! https://goo.gl/JQ8Nys How to Prove a Function is Uniformly Continuous. This is a proof that f(x) = 1/(1 + x^2) is uniformly continuous on R. I hope this video helps.

From playlist Calculus

Video thumbnail

Math 131 Fall 2018 101018 Continuity and Compactness

Definition: bounded function. Continuous image of compact set is compact. Continuous image in Euclidean space of compact set is bounded. Extreme Value Theorem. Continuous bijection on compact set has continuous inverse. Definition of uniform continuity. Continuous on compact set impl

From playlist Course 7: (Rudin's) Principles of Mathematical Analysis (Fall 2018)

Video thumbnail

What are Bounded Sequences? | Real Analysis

What are bounded sequences? We go over the definition of bounded sequence in today's real analysis video lesson. We'll see examples of sequences that are bounded, and some that are bounded above or bounded below, but not both. We say a sequence is bounded if the set of values it takes on

From playlist Real Analysis

Video thumbnail

Every Compact Set in n space is Bounded

Every Compact Set in n space is Bounded If you enjoyed this video please consider liking, sharing, and subscribing. You can also help support my channel by becoming a member https://www.youtube.com/channel/UCr7lmzIk63PZnBw3bezl-Mg/join Thank you:)

From playlist Advanced Calculus

Video thumbnail

Shintaro Nishikawa: Sp(n,1) admits a proper 1-cocycle for a uniformly bounded representation

Talk by Shintaro Nishikawa in Global Noncommutative Geometry Seminar (Americas) http://www.math.wustl.edu/~xtang/NCG-Seminar.html on June 17, 2020.

From playlist Global Noncommutative Geometry Seminar (Americas)

Video thumbnail

Andreas Thom: Asymptotics of Cheeger constants and unitarisability of groups

Talk by Andreas Thom in Global Noncommutative Geometry Seminar (Europe) http://www.noncommutativegeometry.nl/ncgseminar/ on January 26, 2021

From playlist Global Noncommutative Geometry Seminar (Europe)

Video thumbnail

Recovering elliptic curves from their p-torsion - Benjamin Bakker

Benjamin Bakker New York University May 2, 2014 Given an elliptic curve EE over a field kk, its p-torsion EpEp gives a 2-dimensional representation of the Galois group GkGk over 𝔽pFp. The Frey-Mazur conjecture asserts that for k=ℚk=Q and p13p13, EE is in fact determined up to isogeny by th

From playlist Mathematics

Video thumbnail

Hyperbolic 3-manifolds of bounded volume and trace field degre - Bogwang Jeon

Bogwang Jeon, Columbia Univ October 8, 2015 http://www.math.ias.edu/wgso3m/agenda 2015-2016 Monday, October 5, 2015 - 08:00 to Friday, October 9, 2015 - 12:00 This workshop is part of the topical program "Geometric Structures on 3-Manifolds" which will take place during the 2015-2016 aca

From playlist Workshop on Geometric Structures on 3-Manifolds

Video thumbnail

Finding better randomness

Distinguished Visitor Lecture Series Finding better randomness Theodore A. Slaman University of California, Berkeley, USA

From playlist Distinguished Visitors Lecture Series

Video thumbnail

Can p-adic integrals be computed? - William Duke

Automorphic Forms William Duke Thomas Hales April 6, 2001 Concepts, Techniques, Applications and Influence April 4, 2001 - April 7, 2001 Support for this conference was provided by the National Science Foundation Conference Page: https://www.math.ias.edu/conf-automorphicforms Confere

From playlist Mathematics

Video thumbnail

Hyperbolic surfaces and their Teichmüller spaces (Lecture – 03) by Subhojoy Gupta

Geometry, Groups and Dynamics (GGD) - 2017 DATE: 06 November 2017 to 24 November 2017 VENUE: Ramanujan Lecture Hall, ICTS, Bengaluru The program focuses on geometry, dynamical systems and group actions. Topics are chosen to cover the modern aspects of these areas in which research has b

From playlist Geometry, Groups and Dynamics (GGD) - 2017

Video thumbnail

On Sidon Sets - Gilles Pisier

Analysis and Beyond - Celebrating Jean Bourgain's Work and Impact May 22, 2016 More videos on http://video.ias.edu

From playlist Analysis and Beyond

Video thumbnail

Index Theory and Flexibility in Positive Scalar Curve Geometry -Bernhard Hanke

Emerging Topics Working Group Topic: Index Theory and Flexibility in Positive Scalar Curve Geometry Speaker: Bernhard Hanke Affilaion: Augsburg University Date: October 18, 2018 For more video please visit http://video.ias.edu

From playlist Mathematics

Video thumbnail

Rumours, consensus and epidemics on networks (Lecture 2) by A Ganesh

PROGRAM : ADVANCES IN APPLIED PROBABILITY ORGANIZERS : Vivek Borkar, Sandeep Juneja, Kavita Ramanan, Devavrat Shah and Piyush Srivastava DATE & TIME : 05 August 2019 to 17 August 2019 VENUE : Ramanujan Lecture Hall, ICTS Bangalore Applied probability has seen a revolutionary growth in r

From playlist Advances in Applied Probability 2019

Video thumbnail

Continuous implies Bounded

Continuous implies Bounded In this video, I show that any continuous function from a closed and bounded interval to the real numbers must be bounded. The proof is very neat and involves a straightforward application of the Bolzano-Weierstraß Theorem, enjoy! Bolzano-Weierstraß: https://yo

From playlist Limits and Continuity

Related pages

Béla Szőkefalvi-Nagy | Möbius transformation | Locally compact group | Hilbert space | Complementary series representation | Operator norm | Induced representation | Von Neumann conjecture | Strong operator topology | Unitary representation | Amenable group | Tits alternative | Cayley graph | Homomorphism | Linear group | Direct product of groups