# Implementing zonal harmonics with the Fueter principle

## TL;DR

This paper introduces new formulas for computing zonal harmonic functions in any dimension using the Fueter theorem and slice regularity, revealing their relation to Hermitian products and providing optimal computational methods.

## Contribution

It provides novel formulas for zonal harmonics based on the Fueter principle and slice regularity, extending their computation to any dimension.

## Key findings

- Zonal harmonics can be expressed via ladder operators acting on constants.
- Explicit formulas relate zonal harmonics to powers of Hermitian products.
- Computational methods are shown to be optimal compared to direct calculations.

## Abstract

By exploiting the Fueter theorem, we give new formulas to compute zonal harmonic functions in any dimension. We first give a representation of them as a result of a suitable ladder operator acting on the constant function equal to one. Then, inspired by recent work of A. Perotti, using techniques from slice regularity, we derive explicit expressions for zonal harmonics starting from the 2 and 3 dimensional cases. It turns out that all zonal harmonics in any dimension are related to the real part of powers of the standard Hermitian product in $\mathbb{C}$. At the end we compare formulas, obtaining interesting equalities involving the real part of positive and negative powers of the standard Hermitian product. In the two appendices we show how our computations are optimal compared to direct ones.