AbstractThe scalar curvature of a Riemannian metric is interesting not only in analysis, geometry, and topology, but also in physics. Enlargeable Length-structures will be introduced and showed that it is a new obstruction to the existence of a Riemannian metric with positive scalar curvature (PSC-metric). Thus, the connected sum of a closed manifold with some of locally CAT(0)-manifolds carry ...
AbstractUnless it is a flat connection, an affine connection cannot be at the same time projectively flat (geodesics being straight lines) and conformal (conformal structure being preserved by parallel transport). This impossibility is examplified by the two standard models of hyperbolic geometry: Beltrami and Poincaré models. We define stiff connections by weakening the conformality hypothesis...
E-mail：qzsy@tsinghua.edu.cn
Address：Qiuzhen College, Tsinghua University, Haidian District, Beijing
© 2024 Tsinghua University. All Rights Reserved 京ICP备15006448号 京公网安备 110402430053 号
