Zeta functions of $\mathbb{F}_p$-Lie algebras and finite $p$-groups
Seungjai Lee
TL;DR
This work develops a constructive blueprint for computing zeta functions counting subalgebras and ideals of finite-dimensional Lie algebras over $\mathbb{F}_p$, and situates these finite-field invariants as tractable proxies for the local $\mathbb{Z}_p$-zeta factors via the Lazard correspondence. It applies the method to a broad spectrum of algebras, deriving explicit formulas for nilpotent and semisimple cases (e.g., $\mathfrak{sl}_2(\mathbb{F}_p)$, $\mathfrak{gl}_2(\mathbb{F}_p)$, Heisenberg, maximal class algebras $M_c$, and free nilpotent rings $\mathfrak{f}_{c,d}$), as well as to Grenham rings and graded/solvable families. The article also connects these finite-field zeta functions to Higman’s PORC conjecture, presenting wild non-PORC behavior in examples tied to elliptic curves and cubic residues, and discusses the limits of $\,\mathbb{F}_p$-data as predictors of $\mathbb{Z}_p$-behavior. Overall, it provides a first systematic framework for $\mathbb{F}_p$-level zeta theory with concrete computations and clear links to $p$-group counting and arithmetic geometry, while outlining open questions about uniformity and depth of finite-quotient approximations. The results suggest that $\mathbb{F}_p$-zeta functions can serve as effective, arithmetic-prone proxies for understanding $p$-group growth and related uniformity phenomena.
Abstract
We study zeta functions enumerating subalgebras or ideals of Lie algebras over finite field of prime order $\mathbb{F}_p$. We first develop a general blueprint method for computing zeta functions of $\mathbb{F}_p$-Lie algebras, and demonstrate its practical applications in detail to obtain explicit formulas for various interesting new examples that are not covered in any known literature yet. For nilpotent cases this also provides zeta functions counting subgroups and normal subgroups of finite $p$-groups of exponent $p$ for almost all primes via the Lazard correspondence. We investigate their connections to the study of finite $p$-groups, and discuss what can be deduced from these finite Dirichlet polynomials.
