scholarly journals An extension of the Glauberman ZJ-theorem

2020 ◽  
pp. 1-17
Author(s):  
M. Yasi̇r Kızmaz
Keyword(s):  
Free Group ◽  
Closed Subgroup ◽  
Characteristic Subgroup ◽  
Normal Subgroups ◽  
Stable Group

Let [Formula: see text] be an odd prime and let [Formula: see text], [Formula: see text] and [Formula: see text] denote the three different versions of Thompson subgroups for a [Formula: see text]-group [Formula: see text]. In this paper, we first prove an extension of Glauberman’s replacement theorem [G. Glauberman, A characteristic subgroup of a p-stable group, Canad. J. Math. 20 (1968) 1101–1135, Theorem 4.1]. Second, we prove the following: Let [Formula: see text] be a [Formula: see text]-stable group and [Formula: see text]. Suppose that [Formula: see text]. If [Formula: see text] is a strongly closed subgroup in [Formula: see text], then [Formula: see text], [Formula: see text] and [Formula: see text] are normal subgroups of [Formula: see text]. Third, we show the following: Let [Formula: see text] be a [Formula: see text]-free group and [Formula: see text]. If [Formula: see text] is a strongly closed subgroup in [Formula: see text], then the normalizers of the subgroups [Formula: see text], [Formula: see text] and [Formula: see text] control strong [Formula: see text]-fusion in [Formula: see text]. We also prove a similar result for a [Formula: see text]-stable and [Formula: see text]-constrained group. Finally, we give a [Formula: see text]-nilpotency criteria, which is an extension of Glauberman–Thompson [Formula: see text]-nilpotency theorem.

A Problem of R. H. Fox

1981 ◽  
Vol 24 (2) ◽  
pp. 129-136 ◽  
Author(s):  
Narain Gupta
Keyword(s):  
Free Group ◽  
Free Groups ◽  
Group Rings ◽  
Normal Subgroups ◽  
Infinite Groups ◽  
Expository Article

The purpose of this expository article is to familiarize the reader with one of the fundamental problems in the theory of infinite groups. We give an up-to-date account of the so-called Fox problem which concerns the identification of certain normal subgroups of free groups arising out of certain ideals in the free group rings. We assume that the reader is familiar with the elementary concepts of algebra.

scholarly journals A note on groups with separable finitely generated subgroups

1987 ◽  
Vol 36 (1) ◽  
pp. 153-160 ◽  
Author(s):  
R. G. Burns ◽  
A. Karrass ◽  
D. Solitar
Keyword(s):  
Free Group ◽  
Finite Rank ◽  
Cyclic Extension ◽  
Normal Subgroups ◽  
Finitely Generated ◽  
Positive Direction ◽  
One Relator Groups

An example is given of an infinite cyclic extension of a free group of finite rank in which not every finitely generated subgroup is finitely separable. This answers negatively the question of Peter Scott as to whether in all finitely generated 3-manifold groups the finitely generated subgroups are finitely separable. In the positive direction it is shown that in knot groups and one-relator groups with centre, the finitely generated normal subgroups are finitely separable.

A Characteristic Subgroup of a p-Stable Group

1968 ◽  
Vol 20 ◽  
pp. 1101-1135 ◽  
Author(s):  
George Glauberman
Keyword(s):  
Finite Group ◽  
Characteristic Subgroup ◽  
Stable Group ◽  
A Finite Group

Let p be a prime, and let S be a Sylow p-subgroup of a finite group G. J. Thompson (13; 14) has introduced a characteristic subgroup JR(S) and has proved the following results:(1.1) Suppose that p is odd. Then G has a normal p-complement if and only if C(Z(S)) and N(JR(S)) have normal p-complements.

scholarly journals A new characteristic subgroup of a p-stable group

2012 ◽  
Vol 368 ◽  
pp. 231-236 ◽  
Author(s):  
George Glauberman ◽  
Ronald Solomon
Keyword(s):  
Characteristic Subgroup ◽  
Stable Group

Free pairs of symmetric and unitary units in normal subgroups of a division ring

2017 ◽  
Vol 16 (06) ◽  
pp. 1750108 ◽  
Author(s):  
Jairo Z. Goncalves
Keyword(s):  
Heisenberg Group ◽  
Free Group ◽  
Group Algebra ◽  
Division Ring ◽  
General Condition ◽  
Normal Subgroups ◽  
Unitary Subgroup

Let [Formula: see text] be the field of fractions of the group algebra [Formula: see text] of the Heisenberg group [Formula: see text], over the field [Formula: see text] of characteristic [Formula: see text]. We show that for some involutions of [Formula: see text] that are not induced from involutions of [Formula: see text], [Formula: see text] contains free symmetric and unitary pairs. We also give a general condition for a normal unitary subgroup of a division ring to contain a free group, and prove a generalization of Lewin’s Conjecture.

scholarly journals Supplementation in groups

2000 ◽  
Vol 42 (1) ◽  
pp. 37-50 ◽  
Author(s):  
Luise-Charlotte Kappe ◽  
Joseph Kirtland
Keyword(s):  
Subject Classification ◽  
Characteristic Subgroup ◽  
Normal Subgroups ◽  
Closure Properties

In this paper, groups are investigated in which all subgroups, all normal subgroups, or all characteristic subgroups have a proper supplement. This supplement can be either an arbitrary subgroup, a normal or a characteristic subgroup, resulting in nine classes of groups. Properties of these classes are studied such as containment and closure properties, and characterizations for several of these classes are given.1991 Mathematics Subject Classification Primary 20E34, Secondary 20E15.

scholarly journals Verbally closed subgroups of free groups

2014 ◽  
Vol 17 (1) ◽  
Author(s):  
Alexei G. Myasnikov ◽  
Vitaly Roman'kov
Keyword(s):  
Free Group ◽  
Closed Subgroup ◽  
Free Groups

Abstract.We prove that every verbally closed subgroup of a free group

scholarly journals Groups with a quotient that contains the original group as a direct factor

1992 ◽  
Vol 45 (3) ◽  
pp. 513-520 ◽  
Author(s):  
Ron Hirshon ◽  
David Meier
Keyword(s):  
Free Group ◽  
Normal Subgroups ◽  
Direct Factor ◽  
Finitely Generated ◽  
Finitely Generated Group ◽  
Finitely Presented Group ◽  
Finitely Generated Groups ◽  
Original Group ◽  
Hopfian Group ◽  
Finitely Presented

We prove that given a finitely generated group G with a homomorphism of G onto G × H, H non-trivial, or a finitely generated group G with a homomorphism of G onto G × G, we can always find normal subgroups N ≠ G such that G/N ≅ G/N × H or G/N ≅ G/N × G/N respectively. We also show that given a finitely presented non-Hopfian group U and a homomorphism φ of U onto U, which is not an isomorphism, we can always find a finitely presented group H ⊇ U and a finitely generated free group F such that φ induces a homomorphism of U * F onto (U * F) × H. Together with the results above this allows the construction of many examples of finitely generated groups G with G ≅ G × H where H is finitely presented. A finitely presented group G with a homomorphism of G onto G × G was first constructed by Baumslag and Miller. We use a slight generalisation of their method to obtain more examples of such groups.

scholarly journals ON THE LOCAL-INDICABILITY COHEN–LYNDON THEOREM

2011 ◽  
Vol 53 (3) ◽  
pp. 637-656 ◽  
Author(s):  
YAGO ANTOLÍN ◽  
WARREN DICKS ◽  
PETER A. LINNELL
Keyword(s):  
Free Group ◽  
Normal Subgroups ◽  
Induction Method ◽  
Free Products ◽  
Detailed Review ◽  
Generating Set ◽  
Inductive Proof ◽  
Trivial Element ◽  
One Relator Groups ◽  
Indicable Group

AbstractFor a group H and a subset X of H, we let HX denote the set {hxh−1 | h ∈ H, x ∈ X}, and when X is a free-generating set of H, we say that the set HX is a Whitehead subset of H. For a group F and an element r of F, we say that r is Cohen–Lyndon aspherical in F if F{r} is a Whitehead subset of the subgroup of F that is generated by F{r}. In 1963, Cohen and Lyndon (D. E. Cohen and R. C. Lyndon, Free bases for normal subgroups of free groups, Trans. Amer. Math. Soc. 108 (1963), 526–537) independently showed that in each free group each non-trivial element is Cohen–Lyndon aspherical. Their proof used the celebrated induction method devised by Magnus in 1930 to study one-relator groups. In 1987, Edjvet and Howie (M. Edjvet and J. Howie, A Cohen–Lyndon theorem for free products of locally indicable groups, J. Pure Appl. Algebra45 (1987), 41–44) showed that if A and B are locally indicable groups, then each cyclically reduced element of A*B that does not lie in A ∪ B is Cohen–Lyndon aspherical in A*B. Their proof used the original Cohen–Lyndon theorem. Using Bass–Serre theory, the original Cohen–Lyndon theorem and the Edjvet–Howie theorem, one can deduce the local-indicability Cohen–Lyndon theorem: if F is a locally indicable group and T is an F-tree with trivial edge stabilisers, then each element of F that fixes no vertex of T is Cohen–Lyndon aspherical in F. Conversely, by Bass–Serre theory, the original Cohen–Lyndon theorem and the Edjvet–Howie theorem are immediate consequences of the local-indicability Cohen–Lyndon theorem. In this paper we give a detailed review of a Bass–Serre theoretical form of Howie induction and arrange the arguments of Edjvet and Howie into a Howie-inductive proof of the local-indicability Cohen–Lyndon theorem that uses neither Magnus induction nor the original Cohen–Lyndon theorem. We conclude with a review of some standard applications of Cohen–Lyndon asphericity.

The abelianization of the congruence IA-automorphism group of a free group

2007 ◽  
Vol 142 (2) ◽  
pp. 239-248 ◽  
Author(s):  
TAKAO SATOH
Keyword(s):  
Automorphism Group ◽  
Free Group ◽  
Quotient Group ◽  
Homology Group ◽  
Integral Homology ◽  
Normal Subgroups ◽  
Finitely Generated ◽  
Homology Groups ◽  
Inner Automorphism

AbstractWe consider the abelianizations of some normal subgroups of the automorphism group of a finitely generated free group. Let Fn be a free group of rank n. For d ≥ 2, we consider a group consisting the automorphisms of Fn which act trivially on the first homology group of Fn with ${\mathbf Z}$/d${\mathbf Z}$-coefficients. We call it the congruence IA-automorphism group of level d and denote it by IAn,d. Let IOn,d be the quotient group of the congruence IA-automorphism group of level d by the inner automorphism group of a free group. We determine the abelianization of IAn,d and IOn,d for n ≥ 2 and d ≥ 2. Furthermore, for n=2 and odd prime p, we compute the integral homology groups of IA2,p for any dimension.

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