scholarly journals Locally graded groups with all subgroups normal-by-finite

1996 ◽  
Vol 60 (2) ◽  
pp. 222-227 ◽  
Author(s):  
Howard Smith ◽  
James Wiegold
Keyword(s):  
Finite Group ◽  
Finite Index ◽  
Finitely Generated ◽  
Locally Finite ◽  
Residually Finite ◽  
Residually Finite Group ◽  
Open Question ◽  
Locally Graded Groups

AbstractIn a paper published in this journal [1], J. T. Buckely, J. C. Lennox, B. H. Neumann and the authors considered the class of CF-groups, that G such that |H: CoreG (H)| is finite for all subgroups H. It is shown that locally finite CF-groups are abelian-by-finite and BCF, that is, there is an integer n such that |H: CoreG(H)| ≤ n for all subgroups H. The present paper studies these properties in the class of locally graded groups, the main result being that locally graded BCF-groups are abelian-by-finite. Whether locally graded CF-groups are BFC remains an open question. In this direction, the following problems is posed. Does there exist a finitely generated infinite periodic residually finite group in which all subgroups are finite or of finite index? Such groups are locally graded and CF but not BCF.

scholarly journals APPROXIMATING THE FIRST L2-BETTI NUMBER OF RESIDUALLY FINITE GROUPS

2011 ◽  
Vol 03 (02) ◽  
pp. 153-160 ◽  
Author(s):  
W. LÜCK ◽  
D. OSIN
Keyword(s):  
Finite Group ◽  
Finite Groups ◽  
Betti Number ◽  
Betti Numbers ◽  
Torsion Group ◽  
Normal Subgroups ◽  
Finitely Generated ◽  
Residually Finite ◽  
Residually Finite Group ◽  
Residually Finite Groups

We show that the first L2-betti number of a finitely generated residually finite group can be estimated from below by using ordinary first betti numbers of finite index normal subgroups. As an application, we construct a finitely generated infinite residually finite torsion group with positive first L2-betti number.

NILPOTENT LINEAR SEMIGROUPS

2006 ◽  
Vol 16 (01) ◽  
pp. 141-160 ◽  
Author(s):  
ERIC JESPERS ◽  
DAVID RILEY
Keyword(s):  
Finite Group ◽  
Lie Algebra ◽  
Associative Algebra ◽  
Burnside Problem ◽  
Finitely Generated ◽  
Residually Finite ◽  
Residually Finite Group ◽  
Adjoint Semigroup ◽  
Restricted Burnside Problem ◽  
Global And Local

We characterize the structure of linear semigroups satisfying certain global and local nilpotence conditions and deduce various Engel-type results. For example, using a form of Zel'manov's solution of the restricted Burnside problem we are able to show that a finitely generated residually finite group is nilpotent if and only if it satisfies a certain 4-generator property of semigroups we call WMN. Methods of linear semigroups then allow us to prove that a linear semigroup is Mal'cev nilpotent precisely when it satisfies WMN. As an application, we show that a finitely generated associative algebra is nilpotent when viewed as a Lie algebra if and only if its adjoint semigroup is WMN.

ELEMENTS OF PRIME POWER ORDER IN RESIDUALLY FINITE GROUPS

2005 ◽  
Vol 15 (03) ◽  
pp. 571-576 ◽  
Author(s):  
PAVEL SHUMYATSKY
Keyword(s):  
Finite Group ◽  
Finite Groups ◽  
Prime Power ◽  
Prime Power Order ◽  
Closed Set ◽  
Locally Finite ◽  
Residually Finite ◽  
Residually Finite Group ◽  
P Elements ◽  
Residually Finite Groups

Let G be a residually finite group satisfying some identity w ≡ 1. Suppose G is generated by a normal commutator-closed set X of p-elements. We prove that G is locally finite.

scholarly journals Some properties of endomorphisms in residually finite groups

1977 ◽  
Vol 24 (1) ◽  
pp. 117-120 ◽  
Author(s):  
Ronald Hirshon
Keyword(s):  
Finite Group ◽  
Positive Integer ◽  
Free Product ◽  
Finite Groups ◽  
Finitely Generated ◽  
Residually Finite ◽  
Residually Finite Group ◽  
Residually Finite Groups ◽  
A Finite Group ◽  
Torsion Free

AbstractIf ε is an endomorphism of a finitely generated residually finite group onto a subgroup Fε of finite index in F, then there exists a positive integer k such that ε is an isomorphism of Fεk. If K is the kernel of ε, then K is a finite group so that if F is a non trivial free product or if F is torsion free, then ε is an isomorphism on F. If ε is an endomorphism of a finitely generated resedually finite group onto a subgroup Fε (not necessatily of ginite index in F) and if the kernel of ε obeys the minimal condition for subgroups then there exists a positive integer k such that ε is an isomorphism on Fεk.

Groups Whose Subgroup Growth is Less than Linear

1997 ◽  
Vol 07 (01) ◽  
pp. 77-91 ◽  
Author(s):  
Aner Shalev
Keyword(s):  
Finite Group ◽  
Finite Index ◽  
Residually Finite ◽  
Subgroup Growth ◽  
Residually Finite Group ◽  
Finite Quotients

Let G be a residually finite group and let an(G) denote the number of index n subgroups of G. It is shown that an(G)/n →0 if and only if G has a finite index central subgroup whose finite quotients are all cyclic. As an application we show that the degree of a group of polynomial subgroup growth cannot lie strictly between 0 and 1.

A property of finitely generated residually finite groups

1976 ◽  
Vol 15 (3) ◽  
pp. 347-350 ◽  
Author(s):  
P.F. Pickel
Keyword(s):  
Finite Group ◽  
Homomorphic Image ◽  
Finite Groups ◽  
Finitely Generated ◽  
Residually Finite ◽  
Residually Finite Group ◽  
Isomorphism Classes ◽  
Residually Finite Groups ◽  
Finite Quotients ◽  
Relatively Free Group

Let F(G) denote the set of isomorphism classes of finite quotients of the group G. We say that groups G and H have isomorphic finite quotients (IFQ) if F(G) = F(H). In this note, we show that a finitely generated residually finite group G cannot have the same finite quotients as a proper homomorphic image (G is IFQ hopfian). We then obtain some results on groups with the same finite quotients as a relatively free group.

scholarly journals On periodic groups having almost regular 2-elements

1998 ◽  
Vol 41 (2) ◽  
pp. 385-391 ◽  
Author(s):  
N. R. Rocco ◽  
P. Shumyatsky
Keyword(s):  
Finite Group ◽  
Locally Finite ◽  
Residually Finite ◽  
Residually Finite Group ◽  
Periodic Groups

We show that if a periodic residually-finite group G has a 2-element with finite centralizer then G is locally finite.

scholarly journals ON LOCAL FINITENESS OF PERIODIC RESIDUALLY FINITE GROUPS

2002 ◽  
Vol 45 (3) ◽  
pp. 717-721 ◽  
Author(s):  
Mahmut Kuzucuoğlu ◽  
Pavel Shumyatsky
Keyword(s):  
Finite Group ◽  
Finite Groups ◽  
Nilpotent Subgroup ◽  
Subject Classification ◽  
Locally Finite ◽  
Residually Finite ◽  
Residually Finite Group ◽  
Local Finiteness ◽  
Residually Finite Groups

AbstractLet $G$ be a periodic residually finite group containing a nilpotent subgroup $A$ such that $C_G(A)$ is finite. We show that if $\langle A,A^g\rangle$ is finite for any $g\in G$, then $G$ is locally finite.AMS 2000 Mathematics subject classification: Primary 20F50

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