Abstract
For any Wulff shape W, its dual Wulff shape and spherical Wulff shape \(\widetilde{W}\) can be defined naturally. A self-dual Wulff shape is a Wulff shape equaling its dual Wulff shape exactly. In this paper, we prove that a polytope is self-dual if and only if its spherical Wulff shape is a spherical convex body of constant width. We also prove that a smooth Wulff shape is self-dual if and only if for any interior points P of \(\widetilde{W}\) and for any point Q of the intersection of the boundary of \(\widetilde{W}\) and the graph of its spherical support function (with respect to P), the image of Q under the spherical blow-up (with respect to P) is always a point of \(\widetilde{W}\). Moreover, we give an affirmative answer to the problem posed by M. Lassak which says that “Do there exist reduced spherical n-dimensional polytopes (possibly some simplices?) on \(\mathbb {S}^n\), where \(n\ge 3\), different from the \(1/2^n\) part of \(\mathbb {S}^n?\)”.
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Acknowledgements
The author would like to thank the anonymous referee for helpful remarks that significantly improved this paper.
Funding
This work was supported, in partial, by Natural Science Basic Research Program of Shaanxi (Program No. 2023-JC-YB-070).
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Han, H. Self-dual Polytope and Self-dual Smooth Wulff Shape. Results Math 79, 134 (2024). https://doi.org/10.1007/s00025-024-02159-7
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DOI: https://doi.org/10.1007/s00025-024-02159-7
Keywords
- Wulff shape
- dual Wulff shape
- self-dual Wulff shape
- spherical convex polytope
- constant width
- spherical polar set