All Questions
Tagged with extreme-points fa.functional-analysis
5 questions
2
votes
1
answer
486
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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}
...
3
votes
1
answer
622
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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?
2
votes
0
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230
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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 ...
0
votes
1
answer
222
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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_{...
4
votes
2
answers
1k
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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 ...