Outputs (4)

Semi-Free Actions with Manifold Orbit Spaces (2020)
Journal Article
Harvey, J., Kerin, M., & Shankar, K. (2020). Semi-Free Actions with Manifold Orbit Spaces. Documenta Mathematica, 25, 2085-2114. https://doi.org/10.25537/dm.2020v25.2085-2114

In this paper, we study smooth, semi-free actions on closed, smooth, simply connected manifolds, such that the orbit space is a smoothable manifold. We show that the only simply connected 5-manifolds admitting a smooth, semi-free circle action with f... Read More about Semi-Free Actions with Manifold Orbit Spaces.

Fake Lens Spaces and Non-Negative Sectional Curvature (2020)
Book Chapter
Goette, S., Kerin, M., & Shankar, K. (2020). Fake Lens Spaces and Non-Negative Sectional Curvature. In O. Dearricott, W. Tuschmann, Y. Nikolayevsky, T. Leistner, & D. Crowley (Eds.), Differential Geometry in the Large (285-290). Cambridge University Press. https://doi.org/10.1017/9781108884136.016

In this short note we observe the existence of free, isometric actions of finite cyclic groups on a family of 2-connected 7-manifolds with non-negative sectional curvature. This yields many new examples including fake, and possible exotic, lens space... Read More about Fake Lens Spaces and Non-Negative Sectional Curvature.

Highly connected 7-manifolds and non-negative sectional curvature (2020)
Journal Article
Goette, S., Kerin, M., & Shankar, K. (2020). Highly connected 7-manifolds and non-negative sectional curvature. Annals of Mathematics, 191(3), 829-892. https://doi.org/10.4007/annals.2020.191.3.3

In this article, a six-parameter family of highly connected 7-manifolds which admit an S O ( 3 ) -invariant metric of non-negative sectional curvature is constructed and the Eells-Kuiper invariant of each is computed. In particular, it follows that a... Read More about Highly connected 7-manifolds and non-negative sectional curvature.

Torus actions on rationally elliptic manifolds (2020)
Journal Article
Galaz-García, F., Kerin, M., & Radeschi, M. (2021). Torus actions on rationally elliptic manifolds. Mathematische Zeitschrift, 297, 197-221. https://doi.org/10.1007/s00209-020-02508-6

An upper bound is obtained on the rank of a torus which can act smoothly and effectively on a smooth, closed (simply connected) rationally elliptic manifold. In the maximal-rank case, the manifolds admitting such actions are classified up to equivari... Read More about Torus actions on rationally elliptic manifolds.