On a symplectic generalization of a Hirzebruch problem

Fuente: arXiv
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Main Authors: Godinho, Leonor, Lindsay, Nicholas, Sabatini, Silvia
Format: Preprint
Published: 2024
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author Godinho, Leonor
Lindsay, Nicholas
Sabatini, Silvia
author_facet Godinho, Leonor
Lindsay, Nicholas
Sabatini, Silvia
contents Motivated by a problem of Hirzebruch, we study $8$-dimensional, closed, symplectic manifolds having a Hamiltonian torus action with isolated fixed points and second Betti number equal to $1$. Such manifolds are automatically positive monotone. Our main result concerns those endowed with a Hamiltonian $T^2$-action and fourth Betti number equal to $2$. We classify their isotropy data, (equivariant) cohomology rings and (equivariant) Chern classes, and prove that they agree with those of certain explicit Fano $4$-folds with torus actions. Moreover, under more general assumptions, we prove several finiteness results concerning Betti and Chern numbers of $8$-dimensional, positive monotone symplectic manifolds with a Hamiltonian torus action.
format Preprint
id arxiv_https___arxiv_org_abs_2403_00949
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle On a symplectic generalization of a Hirzebruch problem
Godinho, Leonor
Lindsay, Nicholas
Sabatini, Silvia
Symplectic Geometry
Algebraic Geometry
53D20, 57M60, 37B05
Motivated by a problem of Hirzebruch, we study $8$-dimensional, closed, symplectic manifolds having a Hamiltonian torus action with isolated fixed points and second Betti number equal to $1$. Such manifolds are automatically positive monotone. Our main result concerns those endowed with a Hamiltonian $T^2$-action and fourth Betti number equal to $2$. We classify their isotropy data, (equivariant) cohomology rings and (equivariant) Chern classes, and prove that they agree with those of certain explicit Fano $4$-folds with torus actions. Moreover, under more general assumptions, we prove several finiteness results concerning Betti and Chern numbers of $8$-dimensional, positive monotone symplectic manifolds with a Hamiltonian torus action.
title On a symplectic generalization of a Hirzebruch problem
topic Symplectic Geometry
Algebraic Geometry
53D20, 57M60, 37B05
url https://arxiv.org/abs/2403.00949