On automorphisms permuting generators in groups of rank two

Author
W. Tomaszewski
Institute of Mathematics,Silesian Technical University,Kaszubska 23,44-100 Gliwice,POLAND
Abstract
Let $F$ be a free group on two generators, and let $\sigma$ be the automorphism of $F$ permuting the generators. Let $N$ be a $\sigma$-invariant, normal subgroup of $F$, and let $\bar{\sigma}$ be the automorphism of $F/N$ induced by $\sigma$. Let $G$ be a group of rank two, and let $\alpha$ be its automorphism of order two. A question we consider is: when is $\alpha$ induced by $\sigma$? We give some examples of groups in which every automorphism of order two is induced by $\sigma$ and examples of groups with an automorphism of order two which is not induced by $\sigma$. We also give an~example of a group which has two non-conjugated automorphisms, both induced by~$\sigma$.
Keywords
free group, generators, automorphism, σ-invariant normal subgroup, induced automorphism, rank two group, automorphism of order two, examples, non-conjugated automorphisms
DOI
doi:10.30970/ms.8.2.207-211
Reference
1. H.S.M. Coxeter, W.O.J. Moser Generators and relations for discrete groups, Springer-Verlag,addr Berlin, Heidelberg, New York– 1972

2. E.I. Khukhro Nilpotent Groups and their Automorphisms, Walter de Gruyte,addr Berlin, New York–1993

3. G. Higman Groups and rings which have automorphisms without non-trivial fixed elements// J. London Math. Soc. V.50–1854 p.8–15

4. O. Macedońska, D. Solitar On binary $\sigma$-invariant words in a group// Contemporary Math. V.169--1994 p.431--449

5. B.H. Neumann Groups with automorphisms that leave only the neutral element fixed// Arch. Math. (Basel) V.7 –1956 p.1–5

6. E. Płonka Symmetric words in nilpotent groups of class $\leq$ 3// Fundamenta Math. V. 97--1977 p.95--103

Pages
207-211
Volume
8
Issue
2
Year
1997
Journal
Matematychni Studii
Full text of paper
pdf
Table of content of issue