An Extension and Refinement of the Brouwer-Schauder-Tychonoff Fixed Point Theorem

Fuente: arXiv
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Main Authors: Cheng, Lixin, Liu, Chulei, Zhang, Wen
Format: Preprint
Published: 2026
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author Cheng, Lixin
Liu, Chulei
Zhang, Wen
author_facet Cheng, Lixin
Liu, Chulei
Zhang, Wen
contents In this paper, we present the Brouwer-Schauder-Tychonoff fixed point theorem on locally convex spaces as the following extension and improvement: Suppose that S is a compact star-shaped subset with respect to p in S with its convexity index alpha(p)>0. Then every continuous self-mapping f has one of the following two properties: (a) The point p is a fixed point of f; (b) f has uncountably many different eigenvalues and eigenvectors. Note that a closed bounded star-shaped set in a locally convex space is convex if and only if alpha=1, and we extend a Brouwer's type fixed-point theorem on compact star-shaped sets in Banach spaces in a more concise manner to locally convex spaces, thereby this is a simplification and an improvement of the Tychonoff fixed-point theorem to compact star-shaped sets.
format Preprint
id arxiv_https___arxiv_org_abs_2602_09853
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle An Extension and Refinement of the Brouwer-Schauder-Tychonoff Fixed Point Theorem
Cheng, Lixin
Liu, Chulei
Zhang, Wen
Functional Analysis
In this paper, we present the Brouwer-Schauder-Tychonoff fixed point theorem on locally convex spaces as the following extension and improvement: Suppose that S is a compact star-shaped subset with respect to p in S with its convexity index alpha(p)>0. Then every continuous self-mapping f has one of the following two properties: (a) The point p is a fixed point of f; (b) f has uncountably many different eigenvalues and eigenvectors. Note that a closed bounded star-shaped set in a locally convex space is convex if and only if alpha=1, and we extend a Brouwer's type fixed-point theorem on compact star-shaped sets in Banach spaces in a more concise manner to locally convex spaces, thereby this is a simplification and an improvement of the Tychonoff fixed-point theorem to compact star-shaped sets.
title An Extension and Refinement of the Brouwer-Schauder-Tychonoff Fixed Point Theorem
topic Functional Analysis
url https://arxiv.org/abs/2602.09853