# What is reflexive Banach space?

## What is reflexive Banach space?

A Banach space. is reflexive if it is linearly isometric to its bidual under this canonical embedding. James’ space is an example of a non-reflexive space which is linearly isometric to its bidual. Furthermore, the image of James’ space under the canonical embedding has codimension one in its bidual.

## Why reflexive spaces are called reflexive?

Let ˜X⊆X∗∗ be the set of such functionals. The correspondence x↦Fx is an isomorphism which does not change the norm: ‖x‖=‖Fx‖. If ˜X=X∗∗, then the space X is called reflexive.

Is a Banach space?

In mathematics, more specifically in functional analysis, a Banach space (pronounced [ˈbanax]) is a complete normed vector space. Banach spaces are named after the Polish mathematician Stefan Banach, who introduced this concept and studied it systematically in 1920–1922 along with Hans Hahn and Eduard Helly.

### Are LP spaces reflexive?

Suppose (Ω, A,µ) is a σ -finite measure space. Let us prove that Lp = Lp(Ω,µ) is reflexive provided 1

### How do you determine a reflexive relationship?

In Maths, a binary relation R across a set X is reflexive if each element of set X is related or linked to itself. In terms of relations, this can be defined as (a, a) ∈ R ∀ a ∈ X or as I ⊆ R where I is the identity relation on A. Thus, it has a reflexive property and is said to hold reflexivity.

What does reflexive property look like?

Defining the Reflexive Property of Equality You are seeing an image of yourself. You could look at the reflexive property of equality as when a number looks across an equal sign and sees a mirror image of itself! Reflexive pretty much means something relating to itself.

#### When a norm linear space is reflexive?

Recall that every normed space X can be isometrically embedded into its bidual by the map (Jx)(ϕ) := ϕ(x), x ∈ X, ϕ ∈ X∗, and X is called reflexive if J is a bijection. (1) Show that lp := lp(N,K) is reflexive for every p ∈ (1,+∞). Solution: Note that J is injective, and hence we only have to show surjectivity.

#### Are Banach spaces finite-dimensional?

Finite-dimensional case A finite-dimensional Banach space is reflexive (the dimension of X∗ is equal to the dimension of X). A Banach space is finite-dimensional if and only if its unit ball is compact.

Is R2 a Banach space?

2.2.1 Examples of Normed and Banach Spaces Example 2.2 The vector space R2 (the plane where points have coordinates with respect to two orthogonal axes) is a normed space with respect to the following norms: 1. ||a||1 = |x|+|y|, where a = (x, y) ∈ R2.

## Is Lp a Banach space?

(Riesz-Fisher) The space Lp for 1 ≤ p < ∞ is a Banach space.

## What are LP spaces used for?

Because of their key role in the mathematical analysis of measure and probability spaces, Lebesgue spaces are used also in the theoretical discussion of problems in physics, statistics, finance, engineering, and other disciplines.

What is meant by reflexive relation?

### Is a Banach space also a metric space?

Every Hilbert space is a Banach space, every Banach space is a metric space, and every metric space is a topological space. Measure spaces don’t belong in this hierarchy.

### What does Banach space mean?

Banach Space: A Banach space is a complete normed vector space in mathematical analysis. That is, the distance between vectors converges closer to each other as the sequence goes on. The term is named after the Polish mathematician Stefan Banach (1892–1945), who is credited as one of the founders of functional analysis. In computer science,

Is the dual of a reflexive Banach space strictly convex?

The strong dual of a reflexive space is reflexive. If a barreled locally convex Hausdorff space is semireflexive then it is reflexive.