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Main Authors: Karshon, Yael, Kuroki, Shintaro
Format: Preprint
Published: 2025
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Online Access:https://arxiv.org/abs/2507.15004
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author Karshon, Yael
Kuroki, Shintaro
author_facet Karshon, Yael
Kuroki, Shintaro
contents An action of a torus T on a manifold M is locally standard if, at each point, the stabilizer is a sub-torus and the non-zero isotropy weights are a basis to its weight lattice. The quotient M/T is then a manifold-with-corners, decorated by a so-called unimodular labelling, which keeps track of the isotropy representations in M, and by a degree two cohomology class with coefficients in the integral lattice of the Lie algebra of T, which encodes the "twistedness" of M over M/T. We classify locally standard smooth actions of T, up to equivariant diffeomorphisms, in terms of triples (Q,lambda,c), where Q is a manifold-with-corners, lambda is a unimodular labelling, and c is a degree two cohomology class with coefficients in the integral lattice.
format Preprint
id arxiv_https___arxiv_org_abs_2507_15004
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Classification of locally standard torus actions
Karshon, Yael
Kuroki, Shintaro
Geometric Topology
Symplectic Geometry
57S12, 57S25
An action of a torus T on a manifold M is locally standard if, at each point, the stabilizer is a sub-torus and the non-zero isotropy weights are a basis to its weight lattice. The quotient M/T is then a manifold-with-corners, decorated by a so-called unimodular labelling, which keeps track of the isotropy representations in M, and by a degree two cohomology class with coefficients in the integral lattice of the Lie algebra of T, which encodes the "twistedness" of M over M/T. We classify locally standard smooth actions of T, up to equivariant diffeomorphisms, in terms of triples (Q,lambda,c), where Q is a manifold-with-corners, lambda is a unimodular labelling, and c is a degree two cohomology class with coefficients in the integral lattice.
title Classification of locally standard torus actions
topic Geometric Topology
Symplectic Geometry
57S12, 57S25
url https://arxiv.org/abs/2507.15004