The Goulden-Harer-Jackson matrix model

Abstract

An alternative formula for the partition function of the Goulden-Harer-Jackson matrix model is derived, in which the Penner and the orthogonal Penner partition functions are special cases of this formula. Then the free energy that computes the parametrized Euler characteristic $\xi^s_g(\gamma)$ of the moduli spaces as yet an unidentified, for $g$ is odd, shows that the expression for $\xi^s_g(\gamma)$ contains the orbifold Euler characteristic of the moduli space of Riemann surfaces of genus $g$, with $s$ punctures for all parameters $\gamma$. The other contributions are written as a linear combinations of Bernoulli polynomials at rational arguments . It is also shown that in the continuum limit, both the Goulden-Harer-Jackson matrix model and the Penner model have the same critical points.