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On conformally flat minimal Legendrian submanifolds in the unit sphere

Published online by Cambridge University Press:  10 May 2024

Cece Li
Affiliation:
School of Mathematics and Statistics, Henan University of Science and Technology, Luoyang 471000, People's Republic of China (ceceli@haust.edu.cn)
Cheng Xing*
Affiliation:
School of Mathematical Sciences and LPMC, Nankai University, Tianjin 300071, People's Republic of China (xingcheng@nankai.edu.cn)
Jiabin Yin
Affiliation:
School of Mathematics and Statistics, Guangxi Normal University, Guilin 541001, People's Republic of China (jiabinyin@126.com)
*
*Corresponding author.

Abstract

This paper is concerned with the study on an open problem of classifying conformally flat minimal Legendrian submanifolds in the $(2n+1)$-dimensional unit sphere $\mathbb {S}^{2n+1}$ admitting a Sasakian structure $(\varphi,\,\xi,\,\eta,\,g)$ for $n\ge 3$, motivated by the classification of minimal Legendrian submanifolds with constant sectional curvature. First of all, we completely classify such Legendrian submanifolds by assuming that the tensor $K:=-\varphi h$ is semi-parallel, which is introduced as a natural extension of $C$-parallel second fundamental form $h$. Secondly, such submanifolds have also been determined under the condition that the Ricci tensor is semi-parallel, generalizing the Einstein condition. Finally, as direct consequences, new characterizations of the Calabi torus are presented.

Type
Research Article
Copyright
Copyright © The Author(s), 2024. Published by Cambridge University Press on behalf of The Royal Society of Edinburgh

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