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Zeitschrift für Analysis und ihre Anwendungen

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Volume 22, Issue 4, 2003, pp. 991–998
DOI: 10.4171/ZAA/1184

Published online: 2003-12-31

A Simple Proof of the Mountain Circle Theorem

Susanna Comparato[1]

(1) University of Perugia, Italy

We give an alternative proof of Fournier-Willem's Mountain Circle Theorem. Our proof, which is simpler than the original one proposed by these authors, is based on a Lusternik-Schnirelman-type theory and some results of elementary Brouwer degree theory.

Keywords: Critical points, Lusternik-Schnirelman category, Fournier-Willem relative categories

Comparato Susanna: A Simple Proof of the Mountain Circle Theorem. Z. Anal. Anwend. 22 (2003), 991-998. doi: 10.4171/ZAA/1184