On the Growth of a Ballistic Deposition Model on Finite Graphs

We revisit a ballistic deposition process introduced by Atar, Athreya and Kang. Let $\mathcal{G}=(V,E)$ be a finite connected graph. We choose independently and uniformly vertices in $\mathcal{G}$. If a vertex $x$ is chosen and the previous height configuration is given by $h=(h_y)_{y \in V} \in \mathbb{N}_0^V$, the height $h_x$ is replaced by $$\tilde{h}_x := 1 + \max_{y \sim x} h_y.$$ We study asymptotic properties of this growth model. We determine the asymptotic growth parameter $\gamma(\mathcal{G} )$ for some graphs and prove a central limit theorem for the fluctuations around $\gamma ( \mathcal{G})$. We also give a new graph-theoretic interpretation of an inequality obtained by Atar et al..