The Mathieu group $M_{23}$ as additive functions on the finite field of size ${2^{11}}$
Yiming Bing, Bright Hu, Ronni Hu, Rhianna Li, Stefan Lu, Finn McDonald, Michael Sun, Nicholas Wolfe, Joshua E. Yao, Leon Zhou, Nathan Zhou · arXiv (Cornell University) · 2022
We explicitly extend the standard permutation action of the Mathieu group $M_{23}$ on a 23 element set $C=C_{23}$ contained in a finite field of $2^{11}$ elements $\mathbb{F}_{2^{11}}$ to additive functions on this finite field. That is we represent $M_{23}$ as functions $\varphi:\mathbb{F}_{2^{11}}\to \mathbb{F}_{2^{11}}$ such that $\varphi(x+y)=\varphi(x)+\varphi(y)$ and $\varphi|_{C}$ is the standard permutation action. We give explicit $11\times 11$ matrices for the pair of standard generators of order $23$ and order $5$, as well as many tables to help facilitate future calculations.