How is a graph not like a manifold?

Fuente: arXiv
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Main Authors: Ayzenberg, Anton, Masuda, Mikiya, Solomadin, Grigory
Format: Preprint
Published: 2022
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author Ayzenberg, Anton
Masuda, Mikiya
Solomadin, Grigory
author_facet Ayzenberg, Anton
Masuda, Mikiya
Solomadin, Grigory
contents For an equivariantly formal action of a compact torus $T$ on a smooth manifold $X$ with isolated fixed points we investigate the global homological properties of the graded poset $S(X)$ of face submanifolds. We prove that the condition of $j$-independency of tangent weights at each fixed point implies $(j+1)$-acyclicity of the skeleta $S(X)_r$ for $r>j+1$. This result provides a necessary topological condition for a GKM graph to be a GKM graph of some GKM manifold. We use particular acyclicity arguments to describe the equivariant cohomology algebra of an equivariantly formal manifold of dimension $2n$ with an $(n-1)$-independent action of $(n-1)$-dimensional torus, under certain colorability assumptions on its GKM graph. This description relates the equivariant cohomology algebra to the face algebra of a simplicial poset. Such observation underlines certain similarity between actions of complexity one and torus manifolds.
format Preprint
id arxiv_https___arxiv_org_abs_2203_10641
institution arXiv
publishDate 2022
record_format arxiv
spellingShingle How is a graph not like a manifold?
Ayzenberg, Anton
Masuda, Mikiya
Solomadin, Grigory
Algebraic Topology
K-Theory and Homology
57S12, 55N91, 13F55, 06A06 (Primary) 55P91, 55U10, 55T25, 57R91, 13H10, 55R20 (Secondary)
For an equivariantly formal action of a compact torus $T$ on a smooth manifold $X$ with isolated fixed points we investigate the global homological properties of the graded poset $S(X)$ of face submanifolds. We prove that the condition of $j$-independency of tangent weights at each fixed point implies $(j+1)$-acyclicity of the skeleta $S(X)_r$ for $r>j+1$. This result provides a necessary topological condition for a GKM graph to be a GKM graph of some GKM manifold. We use particular acyclicity arguments to describe the equivariant cohomology algebra of an equivariantly formal manifold of dimension $2n$ with an $(n-1)$-independent action of $(n-1)$-dimensional torus, under certain colorability assumptions on its GKM graph. This description relates the equivariant cohomology algebra to the face algebra of a simplicial poset. Such observation underlines certain similarity between actions of complexity one and torus manifolds.
title How is a graph not like a manifold?
topic Algebraic Topology
K-Theory and Homology
57S12, 55N91, 13F55, 06A06 (Primary) 55P91, 55U10, 55T25, 57R91, 13H10, 55R20 (Secondary)
url https://arxiv.org/abs/2203.10641