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Related papers: Connectivity versus Lin-Lu-Yau curvature

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For a given multigraph H, a graph G is H-linked, if |G| \geq |H| and for every injective map {\tau}: V (H) \rightarrow V (G), we can find internally disjoint paths in G, such that every edge from uv in H corresponds to a {\tau} (u) - {\tau}…

Combinatorics · Mathematics 2012-06-08 Florian Pfender

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

The second-largest eigenvalue and second-smallest Laplacian eigenvalue of a graph are measures of its connectivity. These eigenvalues can be used to analyze the robustness, resilience, and synchronizability of networks, and are related to…

Combinatorics · Mathematics 2018-07-20 Aida Abiad , Boris Brimkov , Xavier Martinez-Rivera , O Suil , Jingmei Zhang

We investigate the bounds on algebraic connectivity of graphs subject to constraints on the number of edges, vertices, and topology. We show that the algebraic connectivity for any tree on $n$ vertices and with maximum degree $d$ is bounded…

Discrete Mathematics · Computer Science 2014-12-22 Theodore Kolokolnikov

Connectivity (or equivalently, unweighted maximum flow) is an important measure in graph theory and combinatorial optimization. Given a graph $G$ with vertices $s$ and $t$, the connectivity $\lambda(s,t)$ from $s$ to $t$ is defined to be…

Data Structures and Algorithms · Computer Science 2024-12-25 Shyan Akmal

We investigate forbidden subgraph conditions in the complement of a graph that guarantee positive Lin--Lu--Yau curvature. In particular, we prove that every graph whose complement contains no $4$-cycles has positive Lin--Lu--Yau curvature,…

Combinatorics · Mathematics 2026-05-06 Kaizhe Chen , Shiping Liu , Zhe You

In this paper, we introduce a unified framework for defining Lin-Lu-Yau (LLY) Ricci curvature on both undirected and directed hypergraphs. By establishing upper bounds and monotonicity properties for the parameterized curvature…

Differential Geometry · Mathematics 2025-07-08 Yulu Tian , Liang Zhao

Let $G$ be a graph of order $n$ and let $u,v$ be vertices of $G$. Let $\kappa_G(u,v)$ denote the maximum number of internally disjoint $u$-$v$ paths in $G$. Then the average connectivity $\overline{\kappa}(G)$ of $G$, is defined as $…

Combinatorics · Mathematics 2021-07-23 Lucas Mol , Ortrud R. Oellermann , Vibhav Oswal

We consider the connectivity of fiber graphs with respect to Gr\"obner basis and Graver basis moves. First, we present a sequence of fiber graphs using moves from a Gr\"obner basis and prove that their edge-connectivity is lowest possible…

Combinatorics · Mathematics 2015-01-20 Raymond Hemmecke , Tobias Windisch

Let $\mu_2(G)$ be the second smallest Laplacian eigenvalue of a graph $G$. The vertex connectivity of $G$, written $\kappa(G)$, is the minimum size of a vertex set $S$ such that $G-S$ is disconnected. Fiedler proved that $\mu_2(G) \le…

Combinatorics · Mathematics 2016-10-05 Suil O

In this paper we characterize the unique graph whose algebraic connectivity is minimum among all connected graphs with given order and fixed matching number or edge covering number, and present two lower bounds for the algebraic…

Combinatorics · Mathematics 2017-09-07 Jing Xu , Yi-Zheng Fan , Ying-Ying Tan

A k-connected graph such that deleting any edge / deleting any vertex / contracting any edge results in a graph which is not k-connected is called minimally / critically / contraction-critically k-connected. These three classes play a…

Combinatorics · Mathematics 2011-01-13 Matthias Kriesell

For a graph $G$, $k(G)$ denotes its connectivity. A graph is super connected if every minimum vertex-cut isolates a vertex. Also $k_{1}$-connectivity of a connected graph is the minimum number of vertices whose deletion gives a disconnected…

Combinatorics · Mathematics 2020-09-11 Khalid Kamyab , Mohsen Ghasemi , Rezvan Varmazyar

Recently, it has been proposed that the natural connectivity can be used to efficiently characterise the robustness of complex networks. Natural connectivity quantifies the redundancy of alternative routes in a network by evaluating the…

Statistical Mechanics · Physics 2010-09-20 Jun Wu , Mauricio Barahona , Yuejin Tan , Hongzhong Deng

In this paper, we consider the Ricci curvature of a directed graph, based on Lin-Lu-Yau's definition. We give some properties of the Ricci curvature, including conditions for a directed regular graph to be Ricci-flat. Moreover, we calculate…

Combinatorics · Mathematics 2018-08-24 Taiki Yamada

Let $\tau(G)$ and $\kappa'(G)$ denote the edge-connectivity and the spanning tree packing number of a graph $G$, respectively. Proving a conjecture initiated by Cioaba and Wong, Liu et al. in 2014 showed that for any simple graph $G$ with…

Combinatorics · Mathematics 2018-08-21 Ruifang Liu , Hong-Jian Lai , Yingzhi Tian

Graph rigidity, the study of vertex realizations in $\mathbb{R}^d$ and the motions that preserve the induced edge lengths, has been the focus of extensive research for decades. Its equivalency to graph connectivity for $d=1$ is well known;…

Combinatorics · Mathematics 2025-12-22 Juan F. Presenza , Ignacio Mas , Juan I. Giribet , J. Ignacio Alvarez-Hamelin

The cyclic edge-connectivity of a graph $G$ is the least $k$ such that there exists a set of $k$ edges whose removal disconnects $G$ into components where every component contains a cycle. We show that for graphs of minimum degree at least…

Combinatorics · Mathematics 2021-04-07 Sinan G. Aksoy , Mark Kempton , Stephen J. Young

An edge subset \( S \subseteq E(G) \) is called a 3-restricted edge-cut if \( G - S \) is disconnected and each component of \( G - S \) contains at least three vertices. The 3-restricted edge-connectivity of a graph \( G \), denoted by \(…

Combinatorics · Mathematics 2025-12-01 Wenxin Wang , Yingzhi Tian

The vertex connectivity of a graph $G$ is the size of the smallest set of vertices $S$ such that $G \setminus S$ is disconnected. For the class of planar graphs, the problem of vertex connectivity is well-studied, both from structural and…

Computational Geometry · Computer Science 2025-06-03 Therese Biedl , Karthik Murali