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Related papers: Simple homotopy invariance of higher signatures

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A simple Hamiltonian manifold is a closed connected symplectic manifold equipped with a Hamiltonian action of a torus T with moment map Phi: M-->t^*, such that the fixed set M^T has exactly two connected components, denoted M_0 and M_1. We…

Symplectic Geometry · Mathematics 2013-08-14 Jean-Claude Hausmann , Tara S. Holm

We show that the S^1-equivariant Yamabe invariant of the 3-sphere, endowed with the Hopf action, is equal to the (non-equivariant) Yamabe invariant of the 3-sphere. More generally, we establish a topological upper bound for the…

Differential Geometry · Mathematics 2015-08-13 Bernd Ammann , Farid Madani , Mihaela Pilca

In this paper, we classify compact simply connected cohomogeneity one manifolds up to equivariant diffeomorphism whose isotropy representation by the connected component of the principal isotropy subgroup has three or less irreducible…

Differential Geometry · Mathematics 2010-06-03 Chenxu He

Fold maps are higher dimensional versions of Morse functions, which play important roles in the studies of smooth manifolds, and such general maps also have been fundamental tools in the studies of smooth manifolds by using generic maps. In…

General Topology · Mathematics 2015-04-16 Naoki Kitazawa

We prove that every stable Hamiltonian structure on a closed oriented three-manifold is stably homotopic to one which is supported (with suitable signs) by an open book.

Symplectic Geometry · Mathematics 2017-05-17 Kai Cieliebak , Evgeny Volkov

We prove an equivalence of categories from formal complex structures with formal holomorphic maps to homotopy algebras over a simple operad with its associated homotopy morphisms. We extend this equivalence to complex manifolds. A complex…

Algebraic Topology · Mathematics 2015-01-19 Joan Millès

We prove that a space whose topological complexity equals 1 is homotopy equivalent to some odd-dimensional sphere. We prove a similar result, although not in complete generality, for spaces X whose higher topological complexity TC_n(X) is…

Algebraic Topology · Mathematics 2012-07-20 Mark Grant , Gregory Lupton , John Oprea

Given a closed $n$-manifold, we consider the set of simple homotopy types of $n$-manifolds within its homotopy type, called its simple homotopy manifold set. We characterise it in terms of algebraic K-theory, the surgery obstruction map,…

Algebraic Topology · Mathematics 2026-04-13 Csaba Nagy , John Nicholson , Mark Powell

In this paper we study the Roe index of the signature operator of manifolds of bounded geometry. Our main result is the proof of the uniform homotopy invariance of this index. In other words we show that, given an orientation-preserving…

Differential Geometry · Mathematics 2022-01-06 Stefano Spessato

The singular set of a generic map $f: M\to F$ of a manifold $M$ of dimension $m\ge 2$ to an oriented surface $F$ is a closed smooth curve $\Sigma(f)$. We study the parity of the number of components of $\Sigma(f)$. The image $f(\Sigma)$ of…

Geometric Topology · Mathematics 2025-07-28 Liam Kahmeyer , Rustam Sadykov

We give explicit formulas for the ranks of the third and fourth homotopy groups of all oriented closed simply-connected four manifolds in terms of their second Betti numbers. We also show that the rational homotopy type of these manifolds…

Algebraic Topology · Mathematics 2007-05-23 S. Terzic

We prove that a Stein manifold admits a closed holomorphic 1-form without zeros in every class of the first cohomology group. We also prove an approximation result for closed holomorphic 1-forms without zeros defined in a neighborhood of a…

Complex Variables · Mathematics 2007-05-23 Irena Majcen

In this note we present a complete proof of the fact that all the submanifolds of a one parameter family of compact symplectic submanifolds inside a compact symplectic manifold are Hamiltonian isotopic.

Symplectic Geometry · Mathematics 2023-07-14 Paolo Antonini , Fabio Cavalletti , Antonio Lerario

We show that for any k>1, stratified sets of finite complexity are insufficient to realize all homology classes of codimension k in all smooth manifolds. We also prove a similar result concerning smooth generic maps whose double-point sets…

Algebraic Topology · Mathematics 2014-03-07 Mark Grant , Andras Szucs

In this short note we prove that any smooth, closed, oriented manifold can be dominated by a codimension 1 submanifold of the sphere.

Geometric Topology · Mathematics 2025-12-11 Vasilii Rozhdestvenskii

We prove that homotopy invariants of finite degree distinguish homotopy classes of maps of a connected compact CW-complex to a nilpotent connected CW-complex with finitely generated homotopy groups.

Algebraic Topology · Mathematics 2012-09-11 Semen Podkorytov

We show that every positive definite closed 4-manifold with $b_2^+>1$ and without 1-handles has a vanishing stable cohomotopy Seiberg-Witten invariant, and thus admits no symplectic structure. We also show that every closed oriented…

Geometric Topology · Mathematics 2019-10-23 Kouichi Yasui

This note serves to record examples of diffeomorphisms of closed smooth $4$-manifolds $X$ that are homotopic but not pseudoisotopic to the identity, and to explain why there are no such examples when $X$ is orientable and its fundamental…

Geometric Topology · Mathematics 2024-09-19 Manuel Krannich , Alexander Kupers

Informally, a homotopy monoid is a monoid-like structure in which properties such as associativity only hold `up to homotopy' in some consistent way. This short paper comprises a rigorous definition of homotopy monoid and a brief analysis…

Quantum Algebra · Mathematics 2009-09-25 Tom Leinster

Closed (and simply-connected) manifolds whose dimensions are greater than 4 are classified via sophisticated algebraic and abstract theory such as surgery theory and homotopy theory. It is difficult to handle 3 or 4-dimensional closed…

Algebraic Topology · Mathematics 2021-09-24 Naoki Kitazawa