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In this paper, we first prove the $f$-mean curvature comparison in a smooth metric measure space when the Bakry-Emery Ricci tensor is bounded from below and $|f|$ is bounded. Based on this, we define a Myers-type compactness theorem by…

微分几何 · 数学 2019-07-10 Seungsu Hwang , Sanghun Lee

In this survey, we study three different notions of curvature that are defined on graphs, namely, combinatorial curvature, Bakry-\'Emery curvature, and Ollivier's Ricci curvature. For each curvature notion, the definition and its motivation…

组合数学 · 数学 2018-03-26 Supanat Kamtue

We prove comparison theorems for the sub-Riemannian distortion coefficients appearing in interpolation inequalities. These results, which are equivalent to a sub-Laplacian comparison theorem for the sub-Riemannian distance, are obtained by…

微分几何 · 数学 2020-03-18 Davide Barilari , Luca Rizzi

We consider generalizations of the drifted Laplacian and the Bakry-\'Emery-Ricci tensor, and we prove a version of the mean curvature comparison theorem. Consequently, we prove a Myers-type theorem and a generalization of the…

微分几何 · 数学 2025-07-18 Andrea M. Mota , Cristiano S. Silva , Juliana F. R. Miranda

The Bakry-Emery tensor gives an analog of the Ricci tensor for a Riemannian manifold with a smooth measure. We show that some of the topological consequences of having a positive or nonnegative Ricci tensor are also valid for the…

微分几何 · 数学 2007-05-23 John Lott

Liu, M\"unch, and Peyerimhoff introduced the notion of Bakry-\'Emery curvature for connection graphs as a means to derive Buser-type bounds on the eigenvalues of connection Laplacians. In this work, we present a reformulation of the…

组合数学 · 数学 2026-04-08 Chunyang Hu , Shiping Liu

Let $M$ be a complete Riemannian manifold possibly with a boundary $\partial M$. For any $C^1$-vector field $Z$, by using gradient/functional inequalities of the (reflecting) diffusion process generated by $L:=\Delta+Z$, pointwise…

概率论 · 数学 2017-09-26 Feng-Yu Wang , Bo Wu

We give rigidity results for the discrete Bonnet-Myers diameter bound and the Lichnerowicz eigenvalue estimate. Both inequalities are sharp if and only if the underlying graph is a hypercube. The proofs use well-known semigroup methods as…

微分几何 · 数学 2017-05-22 Shiping Liu , Florentin Münch , Norbert Peyerimhoff

In this paper, we establish some diameter rigidity for K\"ahler manifolds with positive holomorphic sectional curvature.

微分几何 · 数学 2025-12-16 Jianchun Chu , Man-Chun Lee , Jintian Zhu

We study the radial parts of the Brownian motions on K\"ahler and quaternion K\"ahler manifolds. Thanks to sharp Laplacian comparison theorems, we deduce as a consequence a sharp Cheeger-Yau type lower bound for the heat kernels of such…

微分几何 · 数学 2020-03-13 Fabrice Baudoin , Guang Yang

We study geometry of complete Riemannian manifolds endowed with a weighted measure, where the weight function is of quadratic growth. Assuming the associated Bakry-Emery curvature is bounded from below, we derive a new Laplacian comparison…

微分几何 · 数学 2012-11-19 Ovidiu Munteanu , Jiaping Wang

We prove distance bounds for graphs possessing positive Bakry-\'Emery curvature apart from an exceptional set, where the curvature is allowed to be non-positive. If the set of non-positively curved vertices is finite, then the graph admits…

微分几何 · 数学 2019-03-26 Shiping Liu , Florentin Münch , Norbert Peyerimhoff , Christian Rose

We study the behavior of connections and curvature under the HK/QK correspondence, proving simple formulae expressing the Levi-Civita connection and Riemann curvature tensor on the quaternionic K\"ahler side in terms of the initial…

微分几何 · 数学 2021-04-01 V. Cortés , A. Saha , D. Thung

We first extend Cheeger-Colding Almost Splitting Theorem to smooth metric measure spaces. Arguments utilizing this extension of the Almost Splitting Theorem show that if a smooth metric measure space has almost nonnegative Bakry-Emery Ricci…

微分几何 · 数学 2013-11-06 Maree Jaramillo

We establish the diameter and global weighted volume comparison when the $N$-Bakry-Emery Ricci tensor has a positive lower bound in the spectrum sense.

微分几何 · 数学 2024-12-19 Jianchun Chu , Zihang Hao

In this note we extend a recent result of S. Brendle [3] to Riemannian manifolds with densities and nonnegative Bakry-\'Emery Ricci curvature.

微分几何 · 数学 2021-03-16 Florian Johne

In this article, we examine the behavior of the Riemannian and Hermitian curvature tensors of a Hermitian metric, when one of the curvature tensors obeys all the symmetry conditions of the curvature tensor of a K\"ahler metric. We will call…

微分几何 · 数学 2023-03-31 Bo Yang , Fangyang Zheng

The Bakry-Emery generalized Ricci tensor arises in scalar-tensor gravitation theories in the conformal gauge known as the Jordan frame. Recent results from the mathematics literature show that standard singularity and splitting theorems…

广义相对论与量子宇宙学 · 物理学 2015-06-15 E Woolgar

We study spectral properties and geometric functional inequalities on Riemannian manifolds of dimension $\ge3$ with (finite or countably many) conical singularities $\{z_i\}_{i\in\mathfrak I}$ in the neighborhood of which the largest lower…

微分几何 · 数学 2024-06-12 Karl-Theodor Sturm

A quaternionic K\"ahler manifold M is called {\it positive} if it has positive scalar curvature. The main purpose of this paper is to prove several connectedness theorems for quaternionic immersions in a quaternionic K\"ahler manifold, e.g.…

微分几何 · 数学 2007-05-23 Fuquan Fang