On the Analytic and Geometric Aspects of Obstruction Flatness
摘要
In this paper, we investigate analytic and geometric properties of obstruction flatness of strongly pseudoconvex CR hypersurfaces of dimension 2n − 1. Our first two results concern local aspects. One asserts that any strongly pseudoconvex CR hypersurface M ⊂ ℂn can be osculated at a given point p ∈ M by an obstruction flat one up to order 2n + 4 generally and 2n + 5 if and only if p is an obstruction flat point. In the other result, we show that locally there are non-spherical but obstruction flat CR hypersurfaces with transverse symmetry for n = 2. The final main result in this paper concerns the existence of obstruction flat points on compact, strongly pseudoconvex, 3-dimensional CR hypersurfaces. It asserts that the unit sphere in a negative line bundle over a Riemann surface X always has at least one circle of obstruction flat points.