Boundary behavior of harmonic maps on non-smooth domains and complete negatively curved manifolds

Quasiconformal Harmonic Maps into Negatively Curved Manifolds

Let F : M → N be a harmonic map between complete Riemannian manifolds. Assume that N is simply connected with sectional curvature bounded between two negative constants. If F is a quasiconformal harmonic diffeomorphism, then M supports an infinite dimensional space of bounded harmonic functions. On the other hand, if M supports no non-constant bounded harmonic functions, then any harmonic map o...

Negatively Curved Manifolds with Exotic Smooth Structures

Let M denote a compact real hyperbolic manifold with dimensionm 2: 5 and sectional curvature K = I , and let 1: be an exotic sphere ofdimension m. Given any small number t5 > 0 , we show that there is a finitecovering space M of M satisfying the following properties: the connectedsum M#1: is not diffeomorphic to M, but it is homeomorphic to M; M#1:supports a Riemannian metri...

Topology of Non-negatively Curved Manifolds

An important question in the study of Riemannian manifolds of positive sectional curvature is how to distinguish manifolds that admit a metric with non-negative sectional curvature from those that admit one of positive curvature. Surprisingly, if the manifolds are compact and simply connected, all known obstructions to positive curvature are already obstructions to non-negative curvature. On th...

Non-negatively Curved Cohomogeneity One Manifolds

Non-negatively Curved Cohomogeneity One Manifolds Chenxu He Prof. Wolfgang Ziller, Advisor A Riemannian manifold M is called cohomogeneity one if it admits an isometric action by a compact Lie group G and the orbit space is one dimension. Many new examples of non-negatively curved manifolds were discovered recently in this category. However not every cohomogeneity one manifold carries an invari...

Stable Exponentially Harmonic Maps Between Finsler Manifolds