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We characterize cohomogeneity one manifolds and homogeneous spaces with a compact Lie group action admitting an invariant metric with positive scalar curvature.

Differential Geometry · Mathematics 2022-03-14 Georg Frenck , Fernando Galaz-Garcia , Philipp Reiser

We consider conformal metrics of constant curvature 1 on a Riemann surface, with finitely many prescribed conic singularities and prescribed angles at these singularities. Especially interesting case which was studied by C. L. Chai, C. S…

Differential Geometry · Mathematics 2021-03-25 Alexandre Eremenko

We introduce an alternative formalization of curved spaces in which the concept of a pointwise affine space, as defined here, replaces that of a manifold. New or modified definitions of familiar notions from differential geometry such as…

Differential Geometry · Mathematics 2025-09-09 Dan Jonsson

We prove that any smooth Riemannian manifold of non-negative scalar curvature and with a strictly mean convex and compact boundary component can be (C^2) extended beyond the component to have non-negative scalar curvature and to enjoy…

Differential Geometry · Mathematics 2012-09-21 Martin Reiris

We present a detailed study of the curvature and symplectic asphericity properties of symmetric products of surfaces. We show that these spaces can be used to answer nuanced questions arising in the study of closed Riemannian manifolds with…

Geometric Topology · Mathematics 2026-04-23 Luca F. Di Cerbo , Alexander Dranishnikov , Ekansh Jauhari

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

We confirm a conjecture of Hamilton: On compact manifolds the normalized Ricci flow evolves metrics with positive curvature operators to limit metrics with constant curvature.

Differential Geometry · Mathematics 2007-05-23 Christoph Boehm , Burkhard Wilking

The curvature discussed in this paper is a rather far going generalization of the Riemannian sectional curvature. We define it for a wide class of optimal control problems: a unified framework including geometric structures such as…

Differential Geometry · Mathematics 2018-11-30 Andrei Agrachev , Davide Barilari , Luca Rizzi

We classify the Lagrangian orientable surfaces in complex space forms with the property that the ellipse of curvature is always a circle. As a consequence, we obtain new characterizations of the Clifford torus of the complex projective…

Differential Geometry · Mathematics 2015-06-26 Ildefonso Castro

A Riemannian manifold is called almost positively curved if the set of points for which all $2$-planes have positive sectional curvature is open and dense. We find three new examples of almost positively curved manifolds: $Sp(3)/Sp(1)^2$,…

Differential Geometry · Mathematics 2020-08-07 Jason DeVito

We study the rigidity of compact submanifolds of Riemannian manifolds of arbitrary codimension that satisfy a sharp pinching condition involving the norm of the second fundamental form and the mean curvature. Without assuming that the…

Differential Geometry · Mathematics 2026-03-25 Theodoros Vlachos

To any metric spaces there is an associated metric profile. The rectifiability of the metric profile gives a good notion of curvature of a sub-Riemannian space. We shall say that a curvature class is the rectifiability class of the metric…

Metric Geometry · Mathematics 2007-05-23 Marius Buliga

Is a sequence of Riemannian manifolds with positive scalar curvature, satisfying some conditions to keep the sequence reasonable, compact? What topology should one use for the convergence and what is the regularity of the limit space? In…

Differential Geometry · Mathematics 2024-06-07 Brian Allen , Wenchuan Tian , Changliang Wang

A Lagrangian submanifold in an almost Calabi-Yau manifold is called positive if the real part of the holomorphic volume form restricted to it is positive. An exact isotopy class of positive Lagrangian submanifolds admits a natural…

Symplectic Geometry · Mathematics 2014-09-09 Jake P. Solomon

We study curvature-adapted submanifolds of general symmetric spaces. We generalize Cartan's theorem for isoparametric hypersurfaces of spheres and Wang's classification of isoparametric Hopf hypersurfaces in complex projective spaces to any…

Differential Geometry · Mathematics 2012-02-21 Thomas Murphy

In this article, we develop a new index theory for noncompact manifolds endowed with an admissible exhaustion by compact sets. This index theory allows us to provide examples of noncompact manifolds with exotic positive scalar curvature…

K-Theory and Homology · Mathematics 2015-06-15 Stanley Chang , Shmuel Weinbeger , Guoliang Yu

We present a survey of some results and questions related to the notion of scalar curvature in the setting of symplectic supermanifolds.

Differential Geometry · Mathematics 2018-05-11 Rosalía Hernández-Amador , Juan Monterde , José A Vallejo

We study obstructions to the existence of Riemannian metrics of positive scalar curvature on closed smooth manifolds arising from torsion classes in the integral homology of their fundamental groups. As an application, we construct new…

Differential Geometry · Mathematics 2024-07-31 Misha Gromov , Bernhard Hanke

Let $M$ be a closed complex submanifold in ${\mathbb C}^N$ with the complete K\"ahler metric induced by the Euclidean metric. Several finiteness theorems on the $L^p$ Bergman space of holomorphic sections of a given Hermitian line bundle…

Complex Variables · Mathematics 2020-09-21 Bo-Yong Chen , Yuanpu Xiong

In this note, we introduce a new type of positivity condition for the curvature of a Hermitian manifold, which generalizes the notion of nonnegative quadratic orthogonal bisectional curvature to the non-K\"ahler case. We derive a Bochner…

Differential Geometry · Mathematics 2020-10-05 Freid Tong