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arXiv · 1202.5346

Compactly convex sets in linear topological spaces

T. Banakh·M. Mitrofanov·O. Ravsky
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Abstract

A convex subset X of a linear topological space is called compactly convex if there is a continuous compact-valued map $\Phi:X\to exp(X)$ such that $[x,y]\subset\Phi(x)\cup \Phi(y)$ for all $x,y\in X$. We prove that each convex subset of the plane is compactly convex. On the other hand, the space $R^3$ contains a convex set that is not compactly convex. Each compactly convex subset $X$ of a linear topological space $L$ has locally compact closure $\bar X$ which is metrizable if and only if each compact subset of $X$ is metrizable.

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T. Banakh, M. Mitrofanov, O. Ravsky. 2012-02-23. Compactly convex sets in linear topological spaces. https://arxiv.org/abs/1202.5346

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