Gradient estimates on graphs with the $CD\psi(n,-K)$condition

Abstract

This paper investigates gradient estimates on graphs satisfying the $CD\psi(n,-K)$ condition with positive constants $n,K$, and concave $C^{1}$ functions $\psi:(0,+\infty)\rightarrow\mathbb{R}$. Our study focuses on gradient estimates for positive solutions of the heat equation $\partial_{t}u=\Delta u$. Additionally, the estimate is extended to a heat-type equation $\partial_{t}u=\Delta u+cu^{\sigma}$, where $\sigma$ is a constant and $c$ is a continuous function defined on $[0,+\infty)$. Furthermore, we utilize these estimates to derive heat kernel bounds and Harnack inequalities.