Tweaking the constant in the Linear Hadwiger Theorem

Norin and Steiner recently proved the Linear Hadwiger Conjecture. That is, there is an absolute constant $C$ such that every graph $G$ satisfies $\chi (G)⩽C\text{had}(G)$, where $\chi (G)$ is the chromatic number and $\text{had}(G)$ is the Hadwiger number of $G$. Their proof gives a non-optimised constant $C$ of order ${10}^{100}$. This paper uses extensive AI-based optimisation to show that every graph $G$ satisfies $\chi (G)⩽\mathrm{19,885,160}\text{had}(G)$.