# 群与图讨论班 Seminars on Groups and Graphs

You are here: Seminars > 2022 > June 21st

# Finite locally primitive 2-designs

## 吴燕妮 Yanni Wu

SUSTech

Time: 16:00-18:00 (GMT+8), Tuesday June 21st, 2022
Location: Tencent Meeting

Abstract: Let $$\mathcal{D}=(\mathcal{P},\mathcal{B})$$ be a $$G$$-locally-primitive $$2$$-$$(v,k,\lambda)$$ design. We say $$G$$ is of type $$(X,Y)$$, or $$(G^\mathcal{P},G^\mathcal{B}) = (X,Y)$$, if $$G$$ acts faithfully and quasi-primitively on $$\mathcal{P}$$ of type $$X$$ and on $$\mathcal{B}$$ of type $$Y$$. In this talk, we discuss the possible quasi-primitive types for $$G.$$ We show that $$(G^\mathcal{P},G^\mathcal{B}) \ne (\mathrm{PA},\mathrm{SD})$$ or $$(\mathrm{PA},\mathrm{CD})$$.

Host: 丁兆宸 Zhaochen Ding

Slides