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arXiv · 2407.03052

On integral Chang-Skjelbred computations with disconnected isotropy groups

Leopold Zoller
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Abstract

The Chang-Skjelbred method computes the cohomology of a suitable space with a torus action from its equivariant one-skeleton. We show that, under certain restrictions on the cohomological torsion, the integral cohomology is encoded in the one-skeleton even in the presence of arbitrary disconnected isotropy groups. We provide applications to Hamiltonian actions as well as to the GKM case. In the latter, our results lead to a modification of the GKM formula for graph cohomology.

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Leopold Zoller. 2024-07-03. On integral Chang-Skjelbred computations with disconnected isotropy groups. https://arxiv.org/abs/2407.03052

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