@article{Li2023, 
author = {YanYan Li},
title = {Symmetry of hypersurfaces and the Hopf Lemma},
year = {2023},
journal = {Mathematics in Engineering},
volume = {5},
number = {5},
pages = {1-9},
keywords = {symmetry, hypersurfaces, mean curvature, higher order curvature, Hopf Lemma},
url = {https://www.sciopen.com/article/10.3934/mine.2023084},
doi = {10.3934/mine.2023084},
abstract = {A classical theorem of A. D. Alexandrov says that a connected compact smooth hypersurface in Euclidean space with constant mean curvature must be a sphere. We give exposition to some results on symmetry properties of hypersurfaces with ordered mean curvature and associated variations of the Hopf Lemma. Some open problems will be discussed.}
}