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The Li-Yau Eigenvalue Estimates and CR Obata Theorem in Pseudohermitian Manifolds "
Prof. Shu-Cheng Chang ( Department of Mathematics, National Taiwan University )

2008 - 04 - 01 (Tue.)
15:00 - 15:50
308, Mathematics Research Center Building (ori. New Math. Bldg.)

In this talk, based on a jointed work with Hung-Lin Chiu, we first have the CR analogue of Li-Yau's eigenvalue estimate on the lower bound estimate of psitive first eigenvalue of the sub-Laplacian in pseudohermitian $(2n+1)$-manifolds. Second, we prove the CR Obata's theorem on a closed pseudohermitian manifold with vanishing torsion. The key step is a discovery of CR analogue of Bochner formula which involving the CR Paneitz operator and nonnegativity of CR Paneitz operator for any closed pseudohermitian $(2n+1)$-manifold with $n>1$.

July 17 - August 15, 2008
Website:http://140.112.50.155/workshop/cssd_2008_poster.pdf