# Flag-transitive non-symmetric $2$-designs with $(r,\lambda)=1$ and exceptional groups of Lie type

## TL;DR

This paper classifies all flag-transitive non-symmetric 2-designs with specific parameters and exceptional Lie type automorphism groups, identifying five classes of such designs with Ree or Suzuki groups as socles.

## Contribution

It provides a complete classification of non-symmetric 2-designs with (r,λ)=1 and exceptional Lie type automorphism groups, highlighting five distinct classes.

## Key findings

- T must be a Ree or Suzuki group
- Five classes of non-isomorphic designs identified
- Complete classification of designs with given parameters

## Abstract

This paper determined all pairs $(\mathcal{D},G)$ where $\mathcal{D}$ is a non-symmetric 2-$(v,k,\lambda)$ design with $(r,\lambda)=1$ and $G$ is the almost simple flag-transitive automorphism group of $\mathcal{D}$ with an exceptional socle of Lie type. We prove that if $T\trianglelefteq G\leq Aut(T)$ where $T$ is an exceptional group of Lie type, then $T$ must be the Ree group or Suzuki group, and there are five classes of non-isomorphic designs $\mathcal{D}$.