Symmetry and Rigidity of Star-Shaped Coxeter Systems

Fuente: arXiv
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Hauptverfasser: Mahato, Arijit, Naik, Tushar Kanta, Patro, A Rameswar
Format: Preprint
Veröffentlicht: 2026
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author Mahato, Arijit
Naik, Tushar Kanta
Patro, A Rameswar
author_facet Mahato, Arijit
Naik, Tushar Kanta
Patro, A Rameswar
contents We provide a complete description of the automorphism group $\Aut (W)$ of a Coxeter group $W$ admitting a star-shaped finite Coxeter diagram. We prove that each automorphism decomposes as a product of inner and diagram automorphisms, along with three additional types: transvections and two families of partial conjugations. Furthermore, we investigate the natural short exact sequence $1 \to \Inn (W) \to \Aut (W) \to \Out (W) \to 1$. Using Moussong's criteria for hyperbolicity, we show that these groups possess the $R_\infty$-property. Finally, we establish rigidity properties for these groups using known techniques and provide a solution to the isomorphism problem within the class of star-shaped Coxeter systems.
format Preprint
id arxiv_https___arxiv_org_abs_2605_22065
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle Symmetry and Rigidity of Star-Shaped Coxeter Systems
Mahato, Arijit
Naik, Tushar Kanta
Patro, A Rameswar
Group Theory
Primary 20F55, Secondary 20F28, 20E36
We provide a complete description of the automorphism group $\Aut (W)$ of a Coxeter group $W$ admitting a star-shaped finite Coxeter diagram. We prove that each automorphism decomposes as a product of inner and diagram automorphisms, along with three additional types: transvections and two families of partial conjugations. Furthermore, we investigate the natural short exact sequence $1 \to \Inn (W) \to \Aut (W) \to \Out (W) \to 1$. Using Moussong's criteria for hyperbolicity, we show that these groups possess the $R_\infty$-property. Finally, we establish rigidity properties for these groups using known techniques and provide a solution to the isomorphism problem within the class of star-shaped Coxeter systems.
title Symmetry and Rigidity of Star-Shaped Coxeter Systems
topic Group Theory
Primary 20F55, Secondary 20F28, 20E36
url https://arxiv.org/abs/2605.22065