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2 votes
1 answer
486 views

Extreme points of an intersection of convex set with countably many linear spaces

Let $V$ be some `nice' vector space and let $T: V\to \mathbb{R}$ be a linear functional over $V$. Define \begin{align} M= K \cap \bigcup_{i \in \mathbb{N} } \{ v \in V: T(v)=c_i \} \end{align} ...
Boby's user avatar
  • 671
3 votes
1 answer
622 views

A Banach space where the closed unit ball is the convex hull of its extreme points

Let $X$ be a Banach space where the closed unit ball equals the convex hull of its extreme points. Is it true that this implies $X$ is reflexive?
Mark Roelands's user avatar
2 votes
0 answers
230 views

Does Every Extreme Point Maximize Some Linear Functional

Let $L^2$ be the set of all square-integrable functions $f:[0,1] \to [0,1]$ and $S \subset L^2$ be a closed and convex subset of $L^2$ containing the function that is constant and equal to zero. Are ...
Peter's user avatar
  • 355
0 votes
1 answer
222 views

Regarding extreme point in a Banach space

Let $X$ be a Banach space. And let $X^* $ be the dual space of $X$. Let $E_X$ and $E_{X^*}$ denote the extreme points of the unit ball of $X$ and $X^*$. Let $x\in X$ and $|f(x)|=1$ for every $f\in E_{...
user534666's user avatar
4 votes
2 answers
1k views

If the closed unit ball of Banach space has at least one extreme point, must the Banach space the be a dual space?

Let $X$ be a Banach space. By Banach-Alaoglu and Krein-Milman Theorems, one can show that if $X$ is a dual space, then $X$ must have at least one extreme point of the closed unit ball. I am ...
Idonknow's user avatar
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