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Qiang Tu,
Xiaohuan Mu, and
Tiexin Guo
The random Markov-Kakutani fixed point theorem in a random locally convex module
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Published: |
August 20, 2024. |
Keywords: |
Random locally convex modules, stable compactness, random Markov-Kakutani fixed point theorem, random Hahn-Banach theorem. |
Subject [2010]: |
46H25, 41A50, 47H10, 46A22. |
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Abstract
Based on the recently developed theory of σ-stable sets and stable
compactness, we first establish the random Markov-Kakutani fixed point theorem in
a random locally convex module: let (E,P) be a random locally convex
module and G be a nonempty stably compact L0-convex subset of E, then
every commutative family of Tc(Pcc)-continuous
L0-affine mappings from G to G has a common fixed point, where
Pcc is the σ-stable hull of P and
Tc(Pcc) is the locally L0-convex topology induced
by Pcc. Second, we prove that the random Markov-Kakutani fixed point
theorem implies the algebraic form of the known random Hahn-Banach theorem.
Finally, we establish a more general strict separation theorem in a random locally convex
module, which provides not only a more general geometric form of the random
Hahn-Banach theorem but also another proof for the random Markov-Kakutani fixed point
theorem. Therefore, as a byproduct, the work of this paper also shows that the
algebraic and geometric forms of the random Hahn-Banach theorem are equivalent.
It should be pointed out that the main challenge in this paper lies in
overcoming noncompactness since a stably compact set is generally noncompact.
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Acknowledgements
This work was supported by the National Natural Science Foundation of
China (Grant No.12371141) and the Natural Science Foundation of Hunan Province of
China (Grant No.2023JJ30642).
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Author information
Qiang Tu
School of Mathematics and Statistics
Central South University
Changsha, Hunan 410083, China
qiangtu126@126.com
Xiaohuan Mu
School of Mathematics and Statistics
Central South University
Changsha, Hunan 410083, China
xiaohuanmu@163.com
Tiexin Guo
School of Mathematics and Statistics
Central South University
Changsha, Hunan 410083, China
tiexinguo@csu.edu.cn
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