Simply connected Alexandrov 4-manifolds with positive or nonnegative curvature and torus actions
Abstract
We point out that a 4-dimensional topological manifold with an Alexandrov metric (of curvature bounded below) and with an effective, isometric action of the circle or the 2-torus is locally smooth. This observation implies that the topological and equivariant classifications of compact, simply connected Riemannian 4-manifolds with positive or nonnegative sectional curvature and an effective isometric action of a circle or a 2-torus also hold if we consider Alexandrov manifolds instead of Riemannian manifolds.
- Publication:
-
arXiv e-prints
- Pub Date:
- August 2012
- DOI:
- 10.48550/arXiv.1208.3041
- arXiv:
- arXiv:1208.3041
- Bibcode:
- 2012arXiv1208.3041G
- Keywords:
-
- Mathematics - Differential Geometry
- E-Print:
- 10 pages, title changed, results are now proved for Alexandrov 4-manifolds, added examples, simplified proofs