Journal of the
Korean Mathematical Society
JKMS

ISSN(Print) 0304-9914 ISSN(Online) 2234-3008

Article

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J. Korean Math. Soc. 2019; 56(1): 113-125

Online first article July 10, 2018      Printed January 1, 2019

https://doi.org/10.4134/JKMS.j180088

Copyright © The Korean Mathematical Society.

The Ricci curvature on directed graphs

Taiki Yamada

Mathematical Institute in Tohoku University

Abstract

In this paper, we consider the Ricci curvature of a {\em 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 the Ricci curvature of the cartesian product of directed graphs.

Keywords: graph theory, discrete differential geometry

MSC numbers: Primary 05C12; Secondary 52C99