Unstable extremal surfaces of the ``Shiffman-functional''
The author gives a rigorous proof of \textit{M. Shiffman}'s instability result [Ann. Math. (2) 45, 543--576 (1944; Zbl 0063.06963)] at least for the case of a piecewise linear closed Jordan-curve in \(\mathbb{R}^n\). The present paper is a condensed version of the work [\textit{R. Jakob}, ``Instabile Extremalen des Shiffman-Funktionals'', Bonner Mathematische Schriften 362, Bonn: Universität Bonn, Mathematisches Institut (2003; Zbl 1083.49027)].
scientific article; zbMATH DE number 2135743
scientific article