Banach spaces | Operator theory

Approximation property

In mathematics, specifically functional analysis, a Banach space is said to have the approximation property (AP), if every compact operator is a limit of finite-rank operators. The converse is always true. Every Hilbert space has this property. There are, however, Banach spaces which do not; Per Enflo published the first counterexample in a 1973 article. However, much work in this area was done by Grothendieck (1955). Later many other counterexamples were found. The space of bounded operators on does not have the approximation property. The spaces for and (see Sequence space) have closed subspaces that do not have the approximation property. (Wikipedia).

Approximation property
Video thumbnail

Approximating Functions in a Metric Space

Approximations are common in many areas of mathematics from Taylor series to machine learning. In this video, we will define what is meant by a best approximation and prove that a best approximation exists in a metric space. Chapters 0:00 - Examples of Approximation 0:46 - Best Aproximati

From playlist Approximation Theory

Video thumbnail

Polynomial approximations -- Calculus II

This lecture is on Calculus II. It follows Part II of the book Calculus Illustrated by Peter Saveliev. The text of the book can be found at http://calculus123.com.

From playlist Calculus II

Video thumbnail

Linear Approximations and Differentials

Linear Approximation In this video, I explain the concept of a linear approximation, which is just a way of approximating a function of several variables by its tangent planes, and I illustrate this by approximating complicated numbers f without using a calculator. Enjoy! Subscribe to my

From playlist Partial Derivatives

Video thumbnail

Error bounds for Taylor approximations -- Calculus II

This lecture is on Calculus II. It follows Part II of the book Calculus Illustrated by Peter Saveliev. The text of the book can be found at http://calculus123.com.

From playlist Calculus II

Video thumbnail

Polynomial approximation of functions (part 1)

Using a polynomial to approximate a function at f(0). More free lessons at: http://www.khanacademy.org/video?v=sy132cgqaiU

From playlist Calculus

Video thumbnail

Minimax Approximation and the Exchange Algorithm

In this video we'll discuss minimax approximation. This is a method of approximating functions by minimisation of the infinity (uniform) norm. The exchange algorithm is an iterative method of finding the approximation which minimises the infinity norm. FAQ : How do you make these animatio

From playlist Approximation Theory

Video thumbnail

The Lp Norm for Vectors and Functions

In this video, we expand on the idea of L1 and L2 norms, introduced in the previous video to the more general Lp norm. We will get explain how the norms are calculated and try to get an intuition of the differences between the different Lp norms. Chapters 0:00 - Introduction 1:15 - Lp No

From playlist Approximation Theory

Video thumbnail

How to find the position function given the acceleration function

👉 Learn how to approximate the integral of a function using the Reimann sum approximation. Reimann sum is an approximation of the area under a curve or between two curves by dividing it into multiple simple shapes like rectangles and trapezoids. In using the Reimann sum to approximate the

From playlist Riemann Sum Approximation

Video thumbnail

Polynomial approximation of functions (part 2)

Approximating a function with a polynomial by making the derivatives equal at f(0) (Maclauren Series) More free lessons at: http://www.khanacademy.org/video?v=3JG3qn7-Sac

From playlist Calculus

Video thumbnail

Richard Lassaigne: Introduction à la théorie de la complexité

Find this video and other talks given by worldwide mathematicians on CIRM's Audiovisual Mathematics Library: http://library.cirm-math.fr. And discover all its functionalities: - Chapter markers and keywords to watch the parts of your choice in the video - Videos enriched with abstracts, b

From playlist Mathematical Aspects of Computer Science

Video thumbnail

Thomas Ransford: Constructive polynomial approximation in Banach spaces of holomorphic functions

Recording during the meeting "Interpolation in Spaces of Analytic Functions" the November 21, 2019 at the Centre International de Rencontres Mathématiques (Marseille, France) Filmmaker: Guillaume Hennenfent Find this video and other talks given by worldwide mathematicians on CIRM's Audio

From playlist Analysis and its Applications

Video thumbnail

Diego Mondéjar Ruiz (6/10/22): Approximation of compact metric spaces by finite samples

We address the problem of reconstructing topological properties of a compact metric space by means of simpler ones. In this context, we use inverse sequences of finite topological spaces and polyhedra made from finite approximations of the space. This construction is related with Borsuk's

From playlist Vietoris-Rips Seminar

Video thumbnail

Gábor Szabó: "Classification of group actions on C*-algebras"

Actions of Tensor Categories on C*-algebras 2021 Mini Course: "Classification of group actions on C*-algebras" Gábor Szabó - KU Leuven Abstract: This talk will survey the classification of group actions on C*-algebras. One can often observe a rigid behavior of suitable classes of outer a

From playlist Actions of Tensor Categories on C*-algebras 2021

Video thumbnail

DeepMind x UCL RL Lecture Series - Theoretical Fund. of Dynamic Programming Algorithms [4/13]

Research Scientist Diana Borsa explores dynamic programming algorithms as contraction mappings, looking at when and how they converge to the right solutions. Slides: https://dpmd.ai/dynamicprogramming Full video lecture series: https://dpmd.ai/DeepMindxUCL21

From playlist Learning resources

Video thumbnail

Anthony Nouy: Adaptive low-rank approximations for stochastic and parametric equations [...]

Find this video and other talks given by worldwide mathematicians on CIRM's Audiovisual Mathematics Library: http://library.cirm-math.fr. And discover all its functionalities: - Chapter markers and keywords to watch the parts of your choice in the video - Videos enriched with abstracts, b

From playlist Numerical Analysis and Scientific Computing

Video thumbnail

Stability and sofic approximations for product groups and property (tau) - Adrian Ioana

Stability and Testability Topic: Stability and sofic approximations for product groups and property (tau) Speaker: Adrian Ioana Affiliation: University of California, San Diego Date: November 4, 2020 For more video please visit http://video.ias.edu

From playlist Stability and Testability

Video thumbnail

Non-amenable groups admitting no sofic approximation by expander graphs - Gabor Kun

Stability and Testability Topic: Non-amenable groups admitting no sofic approximation by expander graphs Speaker: Gabor Kun Affiliation: Alfréd Rényi Institute of Mathematics Date: February 10, 2021 For more video please visit http://video.ias.edu

From playlist Stability and Testability

Video thumbnail

Anthony Nouy: "Approximation and learning with tree tensor networks"

Tensor Methods and Emerging Applications to the Physical and Data Sciences 2021 Workshop I: Tensor Methods and their Applications in the Physical and Data Sciences "Approximation and learning with tree tensor networks" Anthony Nouy - Université de Nantes Abstract: Tree tensor networks (T

From playlist Tensor Methods and Emerging Applications to the Physical and Data Sciences 2021

Video thumbnail

A nearly optimal lower bound on the approximate degree of AC00- Mark Bun

Computer Science/Discrete Mathematics Seminar I Topic: A nearly optimal lower bound on the approximate degree of AC00 Speaker: A nearly optimal lower bound on the approximate degree of AC00 Speaker: Mark Bun Affiliation: Princeton University Date: October 23, 2017 For more videos, pleas

From playlist Mathematics

Video thumbnail

Accuracy of Taylor approximations - Calculus II

This lecture is on Calculus II. It follows Part II of the book Calculus Illustrated by Peter Saveliev. The text of the book can be found at http://calculus123.com.

From playlist Calculus II

Related pages

Sequence space | Nuclear space | Robert G. Bartle | Compact operator | Hilbert space | Bounded operator | Banach space | Functional analysis | Operator (mathematics) | Mathematics | Lp space | Finite-rank operator | Tsirelson space | Schauder basis | Relatively compact subspace