Genus dependence of the number of (non-)orientable surface triangulations

TL;DR

This paper investigates the enumeration of surface triangulations across different genera using computational methods, revealing genus-independent entropy density and proposing an asymptotic formula for triangulation counts.

Contribution

It applies the Wang-Landau algorithm to compute triangulation numbers for various genera and sizes, providing new asymptotic insights and conjectures.

Findings

Entropy density limit is genus-independent.

Derived next-to-leading order terms.

Proposed asymptotic formula for triangulation counts.

Abstract

Topological triangulations of orientable and non-orientable surfaces with arbitrary genus have important applications in quantum geometry, graph theory and statistical physics. However, until now only the asymptotics for 2-spheres are known analytically, and exact counts of triangulations are only available for both small genus and small triangulations. We apply the Wang-Landau algorithm to calculate the number $N(m,h)$ of triangulations for several order of magnitudes in system size $m$ and genus $h$. We verify that the limit of the entropy density of triangulations is independent of genus and orientability and are able to determine the next-to-leading and the next-to-next-to-leading order terms. We conjecture for the number of surface triangulations the asymptotic behavior \begin{equation*} N(m,h) \rightarrow (170.4 \pm 15.1)^h m^{-2(h - 1)/5} \left( \frac{256}{27} \right)^{m / 2}\;, \end{equation*} what might guide a mathematicians proof for the exact asymptotics.