Displaying similar documents to “On some metabelian 2-groups and applications I”

Compactifications of ℕ and Polishable subgroups of S

Todor Tsankov (2006)

Fundamenta Mathematicae

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We study homeomorphism groups of metrizable compactifications of ℕ. All of those groups can be represented as almost zero-dimensional Polishable subgroups of the group S . As a corollary, we show that all Polish groups are continuous homomorphic images of almost zero-dimensional Polishable subgroups of S . We prove a sufficient condition for these groups to be one-dimensional and also study their descriptive complexity. In the last section we associate with every Polishable ideal on ℕ...

Finite Groups with some s -Permutably Embedded and Weakly s -Permutable Subgroups

Fenfang Xie, Jinjin Wang, Jiayi Xia, Guo Zhong (2013)

Confluentes Mathematici

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Let G be a finite group, p the smallest prime dividing the order of G and P a Sylow p -subgroup of G with the smallest generator number d . There is a set d ( P ) = { P 1 , P 2 , , P d } of maximal subgroups of P such that i = 1 d P i = Φ ( P ) . In the present paper, we investigate the structure of a finite group under the assumption that every member of d ( P ) is either s -permutably embedded or weakly s -permutable in G to give criteria for a group to be p -supersolvable or p -nilpotent.

On the lattice of pronormal subgroups of dicyclic, alternating and symmetric groups

Shrawani Mitkari, Vilas Kharat (2024)

Mathematica Bohemica

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In this paper, the structures of collection of pronormal subgroups of dicyclic, symmetric and alternating groups G are studied in respect of formation of lattices L ( G ) and sublattices of L ( G ) . It is proved that the collections of all pronormal subgroups of A n and S n do not form sublattices of respective L ( A n ) and L ( S n ) , whereas the collection of all pronormal subgroups LPrN ( Dic n ) of a dicyclic group is a sublattice of L ( Dic n ) . Furthermore, it is shown that L ( Dic n ) and LPrN ( Dic n ) are lower semimodular lattices.

On the average number of Sylow subgroups in finite groups

Alireza Khalili Asboei, Seyed Sadegh Salehi Amiri (2022)

Czechoslovak Mathematical Journal

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We prove that if the average number of Sylow subgroups of a finite group is less than 41 5 and not equal to 29 4 , then G is solvable or G / F ( G ) A 5 . In particular, if the average number of Sylow subgroups of a finite group is 29 4 , then G / N A 5 , where N is the largest normal solvable subgroup of G . This generalizes an earlier result by Moretó et al.

Isolated subgroups of finite abelian groups

Marius Tărnăuceanu (2022)

Czechoslovak Mathematical Journal

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We say that a subgroup H is isolated in a group G if for every x G we have either x H or x H = 1 . We describe the set of isolated subgroups of a finite abelian group. The technique used is based on an interesting connection between isolated subgroups and the function sum of element orders of a finite group.

On normal subgroups of compact groups

Nikolay Nikolov, Dan Segal (2014)

Journal of the European Mathematical Society

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Among compact Hausdorff groups G whose maximal profinite quotient is finitely generated, we characterize those that possess a proper dense normal subgroup. We also prove that the abstract commutator subgroup [ H , G ] is closed for every closed normal subgroup H of G .

Modular representations of finite groups with trivial restriction to Sylow subgroups

Paul Balmer (2013)

Journal of the European Mathematical Society

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Let k be a field of characteristic p . Let G be a finite group of order divisible by p and P a p -Sylow subgroup of G . We describe the kernel of the restriction homomorphism T ( G ) T ( P ) , for T ( ) the group of endotrivial representations. Our description involves functions G k × that we call weak P -homomorphisms. These are generalizations to possibly non-normal P G of the classical homomorphisms G / P k × appearing in the normal case.

A note on sumsets of subgroups in * p

Derrick Hart (2013)

Acta Arithmetica

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Let A be a multiplicative subgroup of * p . Define the k-fold sumset of A to be k A = x 1 + . . . + x k : x i A , 1 i k . We show that 6 A * p for | A | > p 11 / 23 + ϵ . In addition, we extend a result of Shkredov to show that | 2 A | | A | 8 / 5 - ϵ for | A | p 5 / 9 .

On the number of isomorphism classes of derived subgroups

Leyli Jafari Taghvasani, Soran Marzang, Mohammad Zarrin (2019)

Czechoslovak Mathematical Journal

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We show that a finite nonabelian characteristically simple group G satisfies n = | π ( G ) | + 2 if and only if G A 5 , where n is the number of isomorphism classes of derived subgroups of G and π ( G ) is the set of prime divisors of the group G . Also, we give a negative answer to a question raised in M. Zarrin (2014).

Every 2 -group with all subgroups normal-by-finite is locally finite

Enrico Jabara (2018)

Czechoslovak Mathematical Journal

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A group G has all of its subgroups normal-by-finite if H / H G is finite for all subgroups H of G . The Tarski-groups provide examples of p -groups ( p a “large” prime) of nonlocally finite groups in which every subgroup is normal-by-finite. The aim of this paper is to prove that a 2 -group with every subgroup normal-by-finite is locally finite. We also prove that if | H / H G | 2 for every subgroup H of G , then G contains an Abelian subgroup of index at most 8 .

On closed subgroups of the group of homeomorphisms of a manifold

Frédéric Le Roux (2014)

Journal de l’École polytechnique — Mathématiques

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Let M be a triangulable compact manifold. We prove that, among closed subgroups of Homeo 0 ( M ) (the identity component of the group of homeomorphisms of M ), the subgroup consisting of volume preserving elements is maximal.

On R -conjugate-permutability of Sylow subgroups

Xianhe Zhao, Ruifang Chen (2016)

Czechoslovak Mathematical Journal

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A subgroup H of a finite group G is said to be conjugate-permutable if H H g = H g H for all g G . More generaly, if we limit the element g to a subgroup R of G , then we say that the subgroup H is R -conjugate-permutable. By means of the R -conjugate-permutable subgroups, we investigate the relationship between the nilpotence of G and the R -conjugate-permutability of the Sylow subgroups of A and B under the condition that G = A B , where A and B are subgroups of G . Some results known in the literature are improved...

Finite groups whose all proper subgroups are 𝒞 -groups

Pengfei Guo, Jianjun Liu (2018)

Czechoslovak Mathematical Journal

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A group G is said to be a 𝒞 -group if for every divisor d of the order of G , there exists a subgroup H of G of order d such that H is normal or abnormal in G . We give a complete classification of those groups which are not 𝒞 -groups but all of whose proper subgroups are 𝒞 -groups.

On decomposability of finite groups

Ruifang Chen, Xianhe Zhao (2017)

Czechoslovak Mathematical Journal

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Let G be a finite group. A normal subgroup N of G is a union of several G -conjugacy classes, and it is called n -decomposable in G if it is a union of n distinct G -conjugacy classes. In this paper, we first classify finite non-perfect groups satisfying the condition that the numbers of conjugacy classes contained in its non-trivial normal subgroups are two consecutive positive integers, and we later prove that there is no non-perfect group such that the numbers of conjugacy classes contained...

On Π -property of some maximal subgroups of Sylow subgroups of finite groups

Zhengtian Qiu, Jianjun Liu, Guiyun Chen (2023)

Czechoslovak Mathematical Journal

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Let H be a subgroup of a finite group G . We say that H satisfies the Π -property in G if for any chief factor L / K of G , | G / K : N G / K ( H K / K L / K ) | is a π ( H K / K L / K ) -number. We study the influence of some p -subgroups of G satisfying the Π -property on the structure of G , and generalize some known results.

On weakly-supplemented subgroups and the solvability of finite groups

Qiang Zhou (2019)

Czechoslovak Mathematical Journal

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A subgroup H of a finite group G is weakly-supplemented in G if there exists a proper subgroup K of G such that G = H K . In this paper, some interesting results with weakly-supplemented minimal subgroups or Sylow subgroups of G are obtained.

Finite groups with some SS-supplemented subgroups

Mengling Jiang, Jianjun Liu (2021)

Czechoslovak Mathematical Journal

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A subgroup H of a finite group G is said to be SS-supplemented in G if there exists a subgroup K of G such that G = H K and H K is S-quasinormal in K . We analyze how certain properties of SS-supplemented subgroups influence the structure of finite groups. Our results improve and generalize several recent results.