Classification of Convex Ancient Solutions to Curve Shortening Flow on the Sphere
We prove that the only closed, embedded ancient solutions to the curve shortening flow on $\mathbb{S}^2$ are equators or shrinking circles, starting at an equator at time $t=-\infty$ and collapsing to the north pole at time $t=0$. To obtain the result, we first prove a Harnack inequality for the cur...
| Main Authors: | , |
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| Format: | Report |
| Language: | unknown |
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arXiv
2014
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| Subjects: | |
| Online Access: | https://dx.doi.org/10.48550/arxiv.1408.5523 https://arxiv.org/abs/1408.5523 |
| Summary: | We prove that the only closed, embedded ancient solutions to the curve shortening flow on $\mathbb{S}^2$ are equators or shrinking circles, starting at an equator at time $t=-\infty$ and collapsing to the north pole at time $t=0$. To obtain the result, we first prove a Harnack inequality for the curve shortening flow on the sphere. Then an application of the Gauss-Bonnet, easily allows us to obtain curvature bounds for ancient solutions leading to backwards smooth convergence to an equator. To complete the proof, we use an Aleksandrov reflection argument to show that maximal symmetry is preserved under the flow. : 16 pages, 1 figure, amsart document class Fixed minor errors in Proposition 2.1 |
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