On the Lagrangian angle and the Kähler angle of immersed surfaces in the complex plane $\bbc^2$
arXiv:1511.02569
Abstract
In this paper, we discuss the Lagrangian angle and the Kähler angle of immersed surfaces in . Firstly, we provide an extension of Lagrangian angle, Maslov form and Maslov class to more general surfaces in than Lagrangian surfaces, and then naturally extend a theorem by J.-M. Morvan to surfaces of constant Kähler angle, together with an application showing that the Maslov class of a compact self-shrinker surface with constant Kähler angle is generally non-vanishing. Secondly, we obtain two pinching results for the Kähler angle which imply rigidity theorems of self-shrinkers with Kähler angle under the condition that , where and denote, respectively, the second fundamental form and the position vector of the surface.