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Sextactic points on a simple closed curve

Published online by Cambridge University Press:  22 January 2016

Gudlaugur Thorbergsson
Affiliation:
Mathematisches Institut, Universität zu Köln, Weyertal 86-90 50931 Köln, Germany, [email protected]
Masaaki Umehara
Affiliation:
Department of Mathematics, Graduate School of Science Hiroshima University, Higashi-Hiroshima, 739-8526, Japan, [email protected]
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Abstract

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We give optimal lower bounds for the number of sextactic points on a simple closed curve in the real projective plane. Sextactic points are after inflection points the simplest projectively invariant singularities on such curves. Our method is axiomatic and can be applied in other situations.

Type
Research Article
Copyright
Copyright © Editorial Board of Nagoya Mathematical Journal 2002

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