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In this paper, we introduce a new notion of curvature on the edges of a graph that is defined in terms of effective resistances. We call this the Ricci--Foster curvature. We study the Ricci flow resulting from this curvature. We prove the…

Combinatorics · Mathematics 2024-03-05 Aleyah Dawkins , Vishal Gupta , Mark Kempton , William Linz , Jeremy Quail , Harry Richman , Zachary Stier

We introduce the notion of integral Ricci curvature $I_{\kappa_0}$ for graphs, which measures the amount of Ricci curvature below a given threshold $\kappa_0$. We focus our attention on the Lin-Lu-Yau Ricci curvature. As applications, we…

Combinatorics · Mathematics 2025-03-24 Xavier Ramos Olivé

In this paper, we consider the Ricci flow with prescribed curvature on the finite graph $G=(V,E)$. For any $e$ in $E$, $$\frac{d\omega(t,e)}{dt} = -(\kappa(t,e)-\kappa^*(e))\omega(t,e), t > 0,$$ where $\omega$ is the weight function,…

Differential Geometry · Mathematics 2026-04-21 Yong Lin , Shuang Liu

Two complete graphs are connected by adding some edges. The obtained graph is called the gluing graph. The more we add edges, the larger the Ricci curvature on it becomes. We calculate the Ricci curvature of each edge on the gluing graph…

Differential Geometry · Mathematics 2018-10-30 Taiki Yamada

Ricci curvature and its associated flow offer powerful geometric methods for analyzing complex networks. While existing research heavily focuses on applications for undirected graphs such as community detection and core extraction, there…

Social and Information Networks · Computer Science 2025-12-12 Juan Zhao , Jicheng Ma , Yunyan Yang , Liang Zhao

An amply regular graph is a regular graph such that any two adjacent vertices have $\alpha$ common neighbors and any two vertices with distance $2$ have $\beta$ common neighbors. We prove a sharp lower bound estimate for the Lin--Lu--Yau…

Combinatorics · Mathematics 2024-06-12 Xueping Huang , Shiping Liu , Qing Xia

In the present paper, we introduce a concept of Ricci curvature on hypergraphs for a nonlinear Laplacian. We prove that our definition of the Ricci curvature is a generalization of Lin-Lu-Yau coarse Ricci curvature for graphs to…

Metric Geometry · Mathematics 2026-01-21 MasaHiro Ikeda , Yu Kitabeppu , Yuuki Takai , Takato Uehara

In a previous work, the authors have introduced a Lin-Lu-Yau type Ricci curvature for directed graphs, and obtained a diameter comparison of Bonnet-Myers type. In this paper, we investigate rigidity properties for the equality case, and…

Differential Geometry · Mathematics 2021-04-26 Ryunosuke Ozawa , Yohei Sakurai , Taiki Yamada

In this paper we compare the combinatorial Ricci curvature on cell complexes and the LLY-Ricci curvature defined on graphs. A cell complex is correspondence to a graph such that the vertexes are cells and the edges are vectors on the cell…

Combinatorics · Mathematics 2018-09-28 Kazuyoshi Watanabe , Taiki Yamada

A goal in network science is the geometrical characterization of complex networks. In this direction, we have recently introduced Forman's discretization of Ricci curvature to the realm of undirected networks. Investigation of this…

Metric Geometry · Mathematics 2018-12-26 Emil Saucan , R. P. Sreejith , R. P. Vivek-Ananth , Jürgen Jost , Areejit Samal

In this paper, we generalize Lin-Lu-Yau's Ricci curvature to weighted graphs and give a simple limit-free definition. We prove two extremal results on the sum of Ricci curvatures for weighted graph. A weighted graph $G=(V,E,d)$ is an…

Combinatorics · Mathematics 2020-11-10 Shuliang Bai , An Huang , Linyuan Lu , Shing-Tung Yau

This article introduces a new approach to discrete curvature based on the concept of effective resistances. We propose a curvature on the nodes and links of a graph and present the evidence for their interpretation as a curvature. Notably,…

Differential Geometry · Mathematics 2022-09-26 Karel Devriendt , Renaud Lambiotte

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

In this paper, we compare Ollivier Ricci curvature and Bakry-\'Emery curvature notions on combinatorial graphs and discuss connections to various types of Ricci flatness. We show that non-negativity of Ollivier Ricci curvature implies…

Combinatorics · Mathematics 2023-10-26 David Cushing , Supanat Kamtue , Riikka Kangaslampi , Shiping Liu , Norbert Peyerimhoff

In this paper, we investigate the prescribed curvature problem associated with a special Lin-Lu-Yau curvature on finite graphs of girth at least 6. We define the corresponding Calabi flow for this curvature type, and establish an equivalent…

Differential Geometry · Mathematics 2026-04-06 Yi Li , Jie Wang , Pingsan Yuan , Chao Zheng

We establish a Harnack inequality for finite connected graphs with non-negative Ricci curvature. As a consequence, we derive an eigenvalue lower bound, extending previous results for Ricci flat graphs.

Combinatorics · Mathematics 2012-07-30 Fan Chung , Yong Lin , Shing-Tung Yau

We study the relationship between discrete analogues of Ricci and scalar curvature that are defined for point clouds and graphs. In the discrete setting, Ricci curvature is replaced by Ollivier-Ricci curvature. Scalar curvature can be…

Discrete Mathematics · Computer Science 2025-10-07 Abigail Hickok , Andrew J. Blumberg

We study the Ollivier-Ricci curvature and its modification introduced by Lin, Lu, and Yau on graphs. We provide a complete characterization of all graphs with Lin-Lu-Yau curvature at least one. We then explore the relationship between the…

Combinatorics · Mathematics 2024-11-21 Moritz Hehl

We introduce a new version of a curvature-dimension inequality for non-negative curvature. We use this inequality to prove a logarithmic Li-Yau inequality on finite graphs. To formulate this inequality, we introduce a non-linear variant of…

Differential Geometry · Mathematics 2014-12-11 Florentin Münch

We explore the interaction between connectivity and Lin-Lu-Yau curvature of graphs systematically. The intuition is that connected graphs with large Lin-Lu-Yau curvature also have large connectivity, and vice versa. We prove that the…

Combinatorics · Mathematics 2025-04-22 Kaizhe Chen , Shiping Liu , Zhe You