Three amalgams with remarkable normal subgroup structures

2005/06/15 by Diego Rattaggi, Rattaggi, Diego · 1 citation
Computer Science · Engineering · Mathematics · #Coding theory and cryptography #FOS: Mathematics #Finite Group Theory Research #Group Theory (math.GR) #graph theory and CDMA systems #math.GR

paper · pdf · doi:10.48550/arxiv.math/0506306

6 pages

arxiv created 2005/06/15 · openalex publication_date 2005/06/15 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28

Abstract

We construct three groups Λ₁, Λ₂, Λ₃, which can all be decomposed as amalgamated products F₉ ∗_F₈₁ F₉ and have very few normal subgroups of finite or infinite index. Concretely, Λ₁ is a simple group, Λ₂ is not simple but has no non-trivial normal subgroup of infinite index, and Λ₃ is not simple but has no proper subgroup of finite index.

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