English

Maximal symplectic torus actions

Symplectic Geometry 2025-12-04 v2 Differential Geometry

Abstract

There are several different notions of maximal torus actions on smooth manifolds, in various contexts: symplectic, Riemannian, complex. In the symplectic context, for the so-called isotropy-maximal actions, as well as for the weaker notion of almost isotropy-maximal actions, we give classifications up to equivariant symplectomorphism. These classification results give symplectic analogues of recent classifications in the complex and Riemannian contexts. Moreover, we deduce that every almost isotropy-maximal symplectic torus action is equivariantly diffeomorphic to a product of a symplectic toric manifold and a torus, answering a question of Ishida. The classification theorems are consequences of Duistermaat and Pelayo's classification of symplectic torus actions with coisotropic orbits.

Keywords

Cite

@article{arxiv.2412.17126,
  title  = {Maximal symplectic torus actions},
  author = {Rei Henigman},
  journal= {arXiv preprint arXiv:2412.17126},
  year   = {2025}
}

Comments

20 pages

R2 v1 2026-06-28T20:45:47.789Z