In this paper we develop the parametrix approach for constructing the heat kernel on a graph $G$. In particular, we highlight two specific cases. First, we consider the case when $G$ is embedded in a Eulidean domain or manifold $\Omega$, and we use a heat kernel associated to $\Omega$ to obtain a formula for the heat kernel on $G$. Second, we consider when $G$ is a subgraph of a larger graph $\widetilde{ G}$, and we obtain a formula for the heat kernel on $G$ from the heat kernel on $\widetilde{ G}$ restricted to $G$.
Categories: math.AP math.CO