The paper studies flag-transitive groups of automorphisms of 2-$(v,k,\lambda )$ designs $\mathcal{D}$ with $(r-\lambda ,k)=1$. In 1968, Peter Dembowski proved that such groups of automorphisms act primitively on the set of points of $\mathcal{D}$. The purpose of the present paper is to reduce the structure of these groups even more, we show that they are affine or almost simple.

中文翻译：

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减少具有 ( r  −  λ , k )=1的 2-( v , k , λ ) 设计的标志传递自同构群

该论文研究了 2-的自同构的标志传递群$(v,克,\lambda )$ 设计 $\mathcal{D}$ 和 $(r-\lambda ,克)=1$. 1968 年，Peter Dembowski 证明了这样的自同构群原始地作用于点集$\mathcal{D}$. 本文的目的是进一步减少这些群的结构，我们证明它们是仿射的或几乎是简单的。