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A topological proof of the Arnold four cusps theorem - MaRDI portal

A topological proof of the Arnold four cusps theorem (Q2903267)

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scientific article; zbMATH DE number 6064188
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A topological proof of the Arnold four cusps theorem
scientific article; zbMATH DE number 6064188

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    A topological proof of the Arnold four cusps theorem (English)
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    8 August 2012
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    generic surface
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    Whitney cusp
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    elliptic metric
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    bending angle
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    caustic
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    semi-cubical vertice
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    \textit{V. I. Arnold} in [Rev. Mat. Univ. Complutense Madr. 8, No. 1, 109--119 (1995; Zbl 0973.53501)] proved a theorem stating that on a generic Riemannian surface which is sufficiently close to a sphere has at least four semi-cubical vertices. The author proves the same fact using the Morse theory and replacing the condition of closeness to the sphere by some less restrictive geometric hypothesis.
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