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Analysis of Internet topologies has shown that the Internet topology has negative curvature, measured by Gromov's "thin triangle condition", which is tightly related to core congestion and route reliability. In this work we analyze the…

Social and Information Networks · Computer Science 2015-01-20 Chien-Chun Ni , Yu-Yao Lin , Jie Gao , Xianfeng David Gu , Emil Saucan

We introduce a notion of a girth-regular graph as a $k$-regular graph for which there exists a non-descending sequence $(a_1, a_2, \dots, a_k)$ (called the signature) giving, for every vertex $u$ of the graph, the number of girth cycles the…

Combinatorics · Mathematics 2019-11-05 Primož Potočnik , Janoš Vidali

We simplify and improve the curvature estimates in the paper: On the conditions to extend Ricci flow(II). Furthermore, we develop some volume estimates for the Ricci flow with bounded scalar curvature. These estimates can be applied to…

Differential Geometry · Mathematics 2011-09-21 Xiuxiong Chen , Bing Wang

We show that any normal metric on a closed biquotient with finite fundamental group has positive Ricci curvature.

Differential Geometry · Mathematics 2007-05-23 Lorenz J. Schwachhöfer

In this paper, we derive Li-Yau inequality for unbounded Laplacian on complete weighted graphs with the assumption of the curvature-dimension inequality $CDE'(n,K)$, which can be regarded as a notion of curvature on graphs. Furthermore, we…

Differential Geometry · Mathematics 2018-01-25 Chao Gong , Yong Lin , Shuang Liu , Shing-Tung Yau

The paper is devoted to Hardy type inequalities on closed manifolds. By means of various weighted Ricci curvatures, we establish several sharp Hardy type inequalities on closed weighted Riemannian manifolds. Our results complement in…

Differential Geometry · Mathematics 2021-07-01 Canjun Meng , Han Wang , Wei Zhao

In this note, we extend the rigidity of Cheng-Yau gradient estimate in \cite{HXY} to surfaces with lower Ricci curvature bound. Motivated by these sharp Cheng-Yau gradient estimates, pointwise Cheng-Yau gradient estimates for higher…

Differential Geometry · Mathematics 2025-11-25 Qixuan Hu , Chengjie Yu

In this paper, we use the theory of Riordan matrices to introduce the notion of a Riordan graph. The Riordan graphs are a far-reaching generalization of the well known and well studied Pascal graphs and Toeplitz graphs, and also some other…

Combinatorics · Mathematics 2019-04-16 Gi-Sang Cheon , Ji-Hwan Jung , Sergey Kitaev , Seyed Ahmad Mojallal

This paper explores the properties of directed graphs, termed generalized action graphs, which exhibit a strong connection to certain number sequences. Focusing on the structural and combinatorial aspects, we investigate the conditions…

Combinatorics · Mathematics 2025-07-31 Sarah Klanderman , Katy McDicken , Amelia Tebbe

We study Riemannian manifolds with boundary under a lower weighted Ricci curvature bound. We consider a curvature condition in which the weighted Ricci curvature is bounded from below by the density function. Under the curvature condition,…

Differential Geometry · Mathematics 2017-12-11 Yohei Sakurai

In this article we consider resistance matrix of a connected graph. For unweighted graph we study some necessary and sufficient conditions for resistance regular graphs. Also we find some relationship between Laplacian matrix and resistance…

Combinatorics · Mathematics 2018-03-28 Deepak Sarma

We prove an existence result for helicoidal graphs with prescribed mean curvature in a large class of warped product spaces which comprises space forms.

Differential Geometry · Mathematics 2008-10-17 M. Dajczer , J. H. de Lira

In this paper we introduce the linear clique-width, linear NLC-width, neighbourhood-width, and linear rank-width for directed graphs. We compare these parameters with each other as well as with the previously defined parameters directed…

Data Structures and Algorithms · Computer Science 2018-12-18 Frank Gurski , Carolin Rehs

In Part I of this work we defined a generalization of the concept of effective resistance to directed graphs, and we explored some of the properties of this new definition. Here, we use the theory developed in Part I to compute effective…

Optimization and Control · Mathematics 2013-10-23 George Forrest Young , Luca Scardovi , Naomi Ehrich Leonard

We derive pointwise curvature estimates for graphical mean curvature flows in higher codimensions. To the best of our knowledge, this is the first such estimates without assuming smallness of first derivatives of the defining map. An…

Differential Geometry · Mathematics 2014-12-03 Knut Smoczyk , Mao-Pei Tsui , Mu-Tao Wang

By definition, the edge-connectivity of a connected graph is no larger than its minimum degree. In this paper, we prove that the edge connectivity of a finite connected graph with non-negative Lin-Lu-Yau curvature is equal to its minimum…

Combinatorics · Mathematics 2026-04-13 Shiping Liu , Qing Xia

Curvature properties of a metric connection with totally skew-symmetric torsion are investigated. It is shown that if either the 3-form $T$ is harmonic, $dT=\delta T=0$ or the curvature of the torsion connection $R\in S^2\Lambda^2$ then the…

Differential Geometry · Mathematics 2024-10-08 Stefan Ivanov , Nikola Stanchev

We consider graphs Sigma^n in R^m with prescribed mean curvature and flat normal bundle. Using techniques of Schoen, Simon and Yau, and Ecker-Huisken, we derive an interior curvature estimate of the form |A|^2<=C/R^2 up to dimension n<=5,…

Analysis of PDEs · Mathematics 2007-05-23 Steffen Froehlich , Sven Winklmann

In this paper we present several curvature estimates for solutions of the Ricci flow which depend on smallness of certain local integrals of the norm of the Riemann curvature tensor.

Differential Geometry · Mathematics 2007-07-17 Rugang Ye

We show that a complete Ricci flow of bounded curvature which begins from a manifold with a Ricci lower bound, local entropy bound, and small local scale-invariant integral curvature control will have global point-wise curvature control at…

Differential Geometry · Mathematics 2022-02-08 Pak-Yeung Chan , Eric Chen , Man-Chun Lee