@article{Lin2024, 
author = {Guijuan Lin and Sujuan Long and Qiqi Zhang},
title = {The upper bound for the first positive eigenvalue of Sub-Laplacian on a compact strictly pseudoconvex hypersurface},
year = {2024},
journal = {AIMS Mathematics},
volume = {9},
number = {9},
pages = {25376-25395},
keywords = {sub-Laplacian, upper bound, the first positive eigenvalue, compact real hypersurfaces, ellipsoids},
url = {https://www.sciopen.com/article/10.3934/math.20241239},
doi = {10.3934/math.20241239},
abstract = {Let  (M2n+1,θ) be a compact strictly pseudoconvex real hypersurfaces equipped with the pseudohermitian structure  θ, and  λ1 be the first positive eigenvalue of sub-Laplacian  Δb on  (M2n+1,θ). In this paper, we will give the upper bound of  λ1 under certain conditions that " ReΔb(ρj+ρj¯)(2Δ~ρρj+|∂ρ|ρ2n−1ρkρjk)≤0 (for some  j)" or " ρjk¯=δjk" holds, and apply these results to the ellipsoids furthermore.}
}