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In this article we prove that antitrees with suitable growth properties are examples of infinite graphs exhibiting strictly positive curvature in various contexts: in the normalized and non-normalized Bakry-\'Emery setting as well in the…

Combinatorics · Mathematics 2018-01-30 David Cushing , Shiping Liu , Florentin Münch , Norbert Peyerimhoff

In this paper, we reformulate the Bakry-\'Emery curvature on a weighted graph in terms of the smallest eigenvalue of a rank one perturbation of the so-called curvature matrix using Schur complement. This new viewpoint allows us to show…

Combinatorics · Mathematics 2022-01-26 David Cushing , Supanat Kamtue , Shiping Liu , Norbert Peyerimhoff

We establish a sharp edge-connectivity estimate for graphs with non-negative Bakry-\'Emery curvature. This leads to a geometric criterion for the existence of a perfect matching. Precisely, we show that any regular graph with non-negative…

Combinatorics · Mathematics 2025-07-25 Kaizhe Chen , Jack H. Koolen , Shiping Liu

We establish for the first time the explicit curvature formulas for the horizontal and vertical edges of the strong product of two regular graphs. We complement this result with showing that there does not exist an analogous formula for the…

Combinatorics · Mathematics 2025-07-08 Guiqiang Mou

Curvature is a fundamental geometric characteristic of smooth spaces. In recent years different notions of curvature have been developed for combinatorial discrete objects such as graphs. However, the connections between such discrete…

Probability · Mathematics 2023-11-09 Pim van der Hoorn , Gabor Lippner , Carlo Trugenberger , Dmitri Krioukov

Ricci curvature was proposed by Ollivier in a general framework of metric measure spaces, and it has been studied extensively in the context of graphs in recent years. In this paper we prove upper bounds for Ollivier's Ricci curvature for…

Combinatorics · Mathematics 2020-08-25 Bhaswar B. Bhattacharya , Sumit Mukherjee

The characterization of complex networks with tools originating in geometry, for instance through the statistics of so-called Ricci curvatures, is a well established tool of network science. There exist various types of such Ricci…

Computational Physics · Physics 2024-02-12 Madhumita Mondal , Areejit Samal , Florentin Münch , Jürgen Jost

We study the Bakry-\'Emery curvature function $\mathcal{K}_{G,x}:(0,\infty]\to \mathbb{R}$ of a vertex $x$ in a locally finite graph $G$ systematically. Here $\mathcal{K}_{G,x}(\mathcal{N})$ is defined as the optimal curvature lower bound…

Combinatorics · Mathematics 2019-04-03 David Cushing , Shiping Liu , Norbert Peyerimhoff

We classify all cubic graphs with either non-negative Ollivier-Ricci curvature or non-negative Bakry-\'Emery curvature everywhere. We show in both curvature notions that the non-negatively curved graphs are the prism graphs and the M\"obius…

Combinatorics · Mathematics 2023-10-26 David Cushing , Riikka Kangaslampi , Valtteri Lipiäinen , Shiping Liu , George William Stagg

We introduce a notion of doubly warped product of weighted graphs that is consistent with the doubly warped product in the Riemannian setting. We establish various discrete Bakry-\'Emery Ricci curvature-dimension bounds for such warped…

Differential Geometry · Mathematics 2021-10-26 Zohreh Fathi , Sajjad Lakzian

In this paper, we establish Betti number estimates for graphs with non-negative Ollivier curvature, and for graphs with non-negative Bakry-\'Emery curvature, providing a discrete analogue of a classical result by Bochner for manifolds.…

Combinatorics · Mathematics 2025-03-17 Moritz Hehl , Florentin Münch

We define a hybrid between Ollvier and Bakry Emery curvature on graphs with dependence on a variable neighborhood. The hexagonal lattice is non-negatively curved under this new curvature notion. Bonnet-Myers diameter bounds and Lichnerowicz…

Combinatorics · Mathematics 2019-06-17 Mark Kempton , Gabor Lippner , Florentin Munch

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…

Differential Geometry · Mathematics 2019-03-26 Shiping Liu , Florentin Münch , Norbert Peyerimhoff , Christian Rose

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…

Combinatorics · Mathematics 2018-03-26 Supanat Kamtue

We prove diameter bounds for graphs having positive Ricci-curvature bound in Bakry-Emery sense. One result using only curvature and maximal vertex degree is sharp in case of hypercubes. The other result depends on an additional dimension…

Differential Geometry · Mathematics 2019-04-03 Shiping Liu , Florentin Münch , Norbert Peyerimhoff

In this paper, we explore the relationship between one of the most elementary and important properties of graphs, the presence and relative frequency of triangles, and a combinatorial notion of Ricci curvature. We employ a definition of…

Combinatorics · Mathematics 2014-08-19 Jürgen Jost , Shiping Liu

The definition of Ricci curvature on graphs in Bakry-\'Emery's sense based on curvature dimension condition was introduced by Lin and Yau [\emph{Math. Res. Lett.}, 2010]. Hua and Lin [\emph{Comm. Anal. Geom.}, 2019] classified unweighted…

Combinatorics · Mathematics 2024-08-20 Huiqiu Lin , Zhe You

We give a new upper bound for the average graph distance in terms of the average Ollivier curvature. Here, the average Ollivier curvature is weighted with the edge betweenness centrality. Moreover, we prove that equality is attained…

Combinatorics · Mathematics 2022-10-03 Florentin Münch

In this article we study two discrete curvature notions, Bakry-\'Emery curvature and Ollivier Ricci curvature, on Cayley graphs. We introduce Right Angled Artin-Coxeter Hybrids (RAACHs) generalizing Right Angled Artin and Coxeter groups…

In this paper, we study curvature dimension conditions on birth-death processes which correspond to linear graphs, i.e., weighted graphs supported on the infinite line or the half line. We give a combinatorial characterization of Bakry and…

Differential Geometry · Mathematics 2017-12-06 Bobo Hua , Florentin Münch
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