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We prove a quantitative upper bound on the filling radius of complete, spin manifolds with uniformly positive scalar curvature using the quantitative operator $K$-theory and index theory.

Differential Geometry · Mathematics 2024-02-29 Jinmin Wang , Zhizhang Xie , Guoliang Yu , Bo Zhu

We develop two connections between the quantitative framework of operator $K$-theory for geometric $C^*$-algebras and the problem of positive scalar curvature. First, we introduce a quantitative notion of higher index and use it to give a…

K-Theory and Homology · Mathematics 2024-09-02 Hao Guo , Zhizhang Xie , Guoliang Yu

The Lichnerowicz formula yields an index theoretic obstruction to positive scalar curvature metrics on closed spin manifolds. The most general form of this obstruction is due to Rosenberg and takes values in the $K$-theory of the group…

Differential Geometry · Mathematics 2011-05-20 Bernhard Hanke

We collect a few guesses on possible implications of a lower bound on the scalar curvature of a Riemannian manifold on the size and shape of this manifold.

Differential Geometry · Mathematics 2017-10-18 Misha Gromov

In this survey article, given a smooth closed manifold M we study the space of Riemannian metrics of positive scalar curvature on M. A long-standing question is: when is this space non-empty (i.e. when does M admit a metric of positive…

Geometric Topology · Mathematics 2015-07-16 Thomas Schick

In this article, we study the topological complexity of manifolds with a lower scalar curvature bound. We introduce a small scale index theorem to establish an upper bound for Gromov's simplicial norm of the Poincar\'e dual of the A-hat…

Differential Geometry · Mathematics 2025-11-05 Qiaochu Ma , Guoliang Yu

In this note, we look at estimates for the scalar curvature k of a Riemannian manifold M which are related to spin^c Dirac operators: We show that one may not enlarge a Kaehler metric with positive Ricci curvature without making k smaller…

Differential Geometry · Mathematics 2008-09-16 S. Goette , U. Semmelmann

In this note, we review some recent developments related to metric aspects of scalar curvature from the point of view of index theory for Dirac operators. In particular, we revisit index-theoretic approaches to a conjecture of Gromov on the…

Differential Geometry · Mathematics 2024-08-15 Rudolf Zeidler

We establish a sharp upper bound for the bottom spectrum of the Beltrami Laplacian on universal covers of closed Riemannian manifolds with scalar curvature lower bound. Moreover, we prove a scalar curvature rigidity theorem when this bound…

Differential Geometry · Mathematics 2025-09-01 Jinmin Wang , Bo Zhu

Positiveness of scalar curvature and Ricci curvature requires vanishing the obstruction $\theta(M)$ which is computed in some KK-theory of C*-algebras index as a pairing of spin Dirac operator and Mishchenko bundle associated to the…

K-Theory and Homology · Mathematics 2017-05-09 Do Ngoc Diep

Using Weitzenb\"ock techniques on any compact Riemannian spin manifold we derive inequalities that involve a real parameter and join the eigenvalues of the Dirac operator with curvature terms. The discussion of these inequalities yields…

Differential Geometry · Mathematics 2009-11-10 K. -D. Kirchberg

Comparison theorems are foundational to our understanding of the geometric features implied by various curvature constraints. This paper considers manifolds with a positive lower bound on either scalar, 2-Ricci, or Ricci curvature, and…

Differential Geometry · Mathematics 2023-05-29 Sven Hirsch , Demetre Kazaras , Marcus Khuri , Yiyue Zhang

We extend the vanishing theorem for the Seiberg-Witten invariants of a manifold with positive scalar curvature to the case when the curvature is allowed to be negative on a set of small volume. (The precise curvature bounds are described in…

Geometric Topology · Mathematics 2007-05-23 Daniel Ruberman

We give a curvature dependent lower bound for the filling radius of all closed Riemannian manifolds as well as an upper one for manifolds which are the total space of a Riemannian submersion. The latter applies also to the case of…

Differential Geometry · Mathematics 2022-06-17 Manuel Cuerno , Luis Guijarro

We prove a Riemannian positive mass theorem for asymptotically flat spin manifolds with hypersurface singularities. Unlike earlier results, some components of the singular set may be mean-concave, provided that other components of the…

Differential Geometry · Mathematics 2026-02-12 Georg Frenck , Bernhard Hanke , Sven Hirsch

We prove a scalar-mean rigidity theorem for compact Riemannian manifolds with boundary in dimension less than five by developing a dimension reduction argument for mean curvature, which extends Schoen-Yau's dimension reduction argument for…

Differential Geometry · Mathematics 2025-03-06 Jinmin Wang , Zhichao Wang , Bo Zhu

Let M be a complete Riemannian manifold, D a Dirac-type operator on M whose Weitzenbock curvature is uniformly positive on the complement of a subset Z of M. We show that the coarse index of D is localized to the K-theory of the coarse…

K-Theory and Homology · Mathematics 2012-11-05 John Roe

We prove a general relative higher index theorem for complete manifolds with positive scalar curvature towards infinity. We apply this theorem to study Riemannian metrics of positive scalar curvature on manifolds. For every two metrics of…

K-Theory and Homology · Mathematics 2012-08-27 Zhizhang Xie , Guoliang Yu

We prove the scalar curvature rigidity for $L^\infty$ metrics on $\mathbb S^n\backslash\Sigma$, where $\mathbb S^n$ is the $n$-dimensional sphere with $n\geq 3$ and $\Sigma$ is a closed subset of $\mathbb S^n$ of codimension at least…

Differential Geometry · Mathematics 2026-05-21 Jinmin Wang , Zhizhang Xie

In this paper, we prove a quantitative relative index theorem. It provides a conceptual framework for studying some conjectures and open questions of Gromov on positive scalar curvature. More precisely, we prove a $\lambda$-Lipschitz…

Differential Geometry · Mathematics 2021-06-28 Zhizhang Xie
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