The sharp lower bound for the first positive eigenvalue of the folland-stein operator on a closed pseudohermitian (2n+1)-manifold

摘要

In this paper, we obtain a sharp lower bound estimate for the first nonzero eigenvalue of the Folland-Stein operator L_c, |c| ≤ n, on a closed pseudohermitian (2n+1)-manifold M. This generalizes the first nonzero eigenvalue estimatesof the sublaplacian and Kohn Laplacian.