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Related papers: On equivariantly formal 2-torus manifolds

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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…

Geometric Topology · Mathematics 2025-07-22 Yael Karshon , Shintaro Kuroki

We prove that any quasitoric manifold $M^{2n}$ admits a $T^n$-invariant almost complex structure if and only if $M$ admits a positive omniorientation. In particular, we show that all obstructions to existence of $T^n$-invariant almost…

Algebraic Topology · Mathematics 2009-04-28 Andrei Kustarev

For every Sol manifold $M$, we determine the $\mathbb{Z}_2$-Thurston norm of every element in $H_2(M;\mathbb{Z}_2)$. Each Sol manifold is either a torus bundle over the circle or a torus semi-bundle, thus corresponds to a torus map. We…

Geometric Topology · Mathematics 2026-03-25 Xiaoming Du , Weibiao Wang

A quasitoric manifold is a $2n$-dimensional compact smooth manifold with a locally standard action of an $n$-dimensional torus whose orbit space is a simple polytope. In this article, we classify quasitoric manifolds with the second Betti…

Algebraic Topology · Mathematics 2012-09-20 Suyoung Choi , Seonjeong Park , Dong Youp Suh

In this paper we survey results and recent progresses on the equivariant bordism classification of 2-torus manifolds and unitary toric manifolds.

Algebraic Topology · Mathematics 2019-09-10 Zhi Lü

Denote by $\mathcal{Z}_5((\mathbb{Z}_2)^3)$ the group, which is also a vector space over $\mathbb{Z}_2$, generated by equivariant unoriented bordism classes of all five-dimensional closed smooth manifolds with effective smooth…

Algebraic Topology · Mathematics 2025-04-15 Yuanxin Guan , Zhi Lü

We show that a singular Riemannian foliation of codimension two on a compact simply-connected Riemannian $(n+2)$-manifold, with regular leaves homeomorphic to the $n$-torus, is given by a smooth effective $n$-torus action. This solves in…

Differential Geometry · Mathematics 2025-12-25 Diego Corro

In this paper we consider a class of connected closed $G$-manifolds with a non-empty finite fixed point set, each $M$ of which is totally non-homologous to zero in $M_G$ (or $G$-equivariantly formal), where $G={\Bbb Z}_2$. With the help of…

Algebraic Topology · Mathematics 2009-02-17 Bo Chen , Zhi Lü

We give a proof of Kontsevich's formality theorem for a general manifold using Fedosov resolutions of algebras of polydifferential operators and polyvector fields. The main advantage of our construction of the formality quasi-isomorphism is…

Quantum Algebra · Mathematics 2007-05-23 Vasiliy Dolgushev

A riemannian manifold is secure if the geodesics between any pair of points in the manifold can be blocked by a finite number of point obstacles. Compact, flat manifolds are secure. A standing conjecture says that these are the only secure,…

Dynamical Systems · Mathematics 2008-06-24 Victor Bangert , Eugene Gutkin

Let T be a torus of dimension at least k and M a T-manifold. M is a GKM_k-manifold if the action is equivariantly formal, has only isolated fixed points, and any k weights of the isotropy representation in the fixed points are linearly…

Differential Geometry · Mathematics 2021-07-26 Oliver Goertsches , Michael Wiemeler

A quasitoric manifold $M$ is a $2n$-dimensional manifold which admits an action of an $n$-dimensional torus which has some nice properties. We determine the isomorphism type of a maximal compact connected Lie-subgroup $G$ of…

Geometric Topology · Mathematics 2015-11-05 Michael Wiemeler

A torus manifold is a closed smooth manifold of dimension $2n$ having an effective smooth $T^n = (S^1)^n$-action with non-empty fixed points. Petrie \cite{petrie:1973} has shown that any homotopy equivalence between a complex projective…

Algebraic Topology · Mathematics 2012-09-03 Suyoung Choi

We consider effective actions of a compact torus $T^{n-1}$ on an even-dimensional smooth manifold $M^{2n}$ with isolated fixed points. We prove that under certain conditions on weights of tangent representations, the orbit space is a…

Algebraic Topology · Mathematics 2019-05-08 V. Cherepanov

We show that the well-known fact that the equivariant cohomology of a torus action is a torsion-free module if and only if the map induced by the inclusion of the fixed point set is injective generalises to actions of arbitrary compact…

Algebraic Topology · Mathematics 2012-03-02 Oliver Goertsches , Sönke Rollenske

Let $\mathcal{M}_{0}^n$ be the class of closed, simply-connected, non-negatively curved Riemannian manifolds admitting an isometric, effective, isotropy-maximal torus action. We prove that if $M\in \mathcal{M}_{0}^n$, then $M$ is…

Differential Geometry · Mathematics 2020-11-26 Christine Escher , Catherine Searle

We prove that, under a simple condition on the cohomology ring, every closed 4-manifold has mod 2 Seiberg-Witten simple type. This result shows that there exists a large class of topological 4-manifolds such that all smooth structures have…

Geometric Topology · Mathematics 2021-03-31 Tsuyoshi Kato , Nobuhiro Nakamura , Kouichi Yasui

The aim of this paper is to classify simply connected 6-dimensional torus manifolds with vanishing odd degree cohomology. It is shown that there is a one-to-one correspondence between equivariant diffeomorphism types of these manifolds and…

Geometric Topology · Mathematics 2016-01-05 Shintaro Kuroki

We study the closure of a complex subtorus in a toric manifold. If the closure of the complex subtorus is a smooth complex submanifold in the toric manifold, then the subtorus action on such submanifold is Hamiltonian. In this case, we may…

Symplectic Geometry · Mathematics 2025-08-14 Kentaro Yamaguchi

Let $C_2$ denote the cyclic group of order two. Given a manifold with a $C_2$-action, we can consider its equivariant Bredon $RO(C_2)$-graded cohomology. In this paper, we develop a theory of fundamental classes for equivariant submanifolds…

Algebraic Topology · Mathematics 2021-12-01 Christy Hazel