ASAlexander Nikolaevich Skiba

Alexander Nikolaevich Skiba

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Alexander Nikolaevich Skiba has a total of 92 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    On Two Classes of Sublattices of the Subgroup Lattice of a Finite Group

    by Muzhi Wang, A-Ming Liu, Alexander N. Skiba

    Let G denote a finite group; σ={σi∣i∈I⊆{0}∪N} be some partition of the set of all primes P, where 0∈I; I be a class of finite σ0-groups that is closed under extensions, epimorphic images, and subgroups and contains all finite soluble σ0-groups. We say that a subgroup A of G is σI-subnormal in G if there is a subgroup chain A=A0≤A1≤⋯≤At=G such that either Ai−1⊴Ai, Ai/(Ai−1)Ai∈I, or Ai/(Ai−1)Ai is a σj-group for some j≠0. In this paper, we prove that the set LσI(G) of all σI-subnormal subgroups of G and some proper subsets of LσI(G) form sublattices of the lattice of all subgroups of G.

  • On weakly $N$-subnormal subgroups of finite groups

    by A-Ming Liu, Muzhi Wang, Vasily G. Safonov, Alexander N. Skiba

    Let G be a finite group and A, N\leq G . Then A_{\operatorname{sn} G} is the subnormal core of A in G , that is, the subgroup of A generated by all subnormal subgroups of G , contained in A ; A^{\operatorname{sn} G} is the subnormal closure of A in G , that is, the intersection of all subnormal subgroups of G containing A . We say that a subgroup A of G is (i) N -subnormal in G if N\cap A^{\operatorname{sn} G}=N\cap A_{\operatorname{sn} G} ; (ii) weakly N -subnormal in G if for some subnormal subgroup T of G we have AT=G and A\cap T\leq S\leq A , where S is N -subnormal in G . In this paper, we consider some applications of these two concepts. In particular, we prove that a finite group G is soluble if and only if G has a normal subgroup N with soluble factor G/N such that in each maximal chain M_{3}< M_{2}< M_{1}< M_{0}= G of G of length 3 , at least one of the subgroups M_{3} , M_{2} or M_{1} is weakly N -subnormal in G .

  • Lattice Characterizations of $p$-Soluble and $p$-Supersoluble Finite Groups

    by A-Ming Liu, Sizhe Wang, V. G. Safonov, A. N. Skiba

    Let \(G\) be a finite group, and let \({\mathcal{L}}(G)\) be the lattice of all subgroups of \(G\). A subgroup \(M\) of \(G\) is called modular in \(G\) if \(M\) is a modular element (in the Kurosh sense) of the lattice \({\mathcal{L}}(G)\), i.e., if (1) \(\langle X,M\cap Z\rangle=\langle X,M\rangle\cap Z\) for all \(X\leq G,Z\leq G\) such that \(X\leq Z\), and (2) \(\langle M,Y\cap Z\rangle=\langle M,Y\rangle\cap Z\) for all \(Y\leq G,Z\leq G\) such that \(M\leq Z\). If \(A\) is a subgroup of \(G\), then \(A_{mG}\) is the subgroup of \(A\) generated by all its subgroups that are modular in \(G\). We say that a subgroup \(A\) is \(N\)-modular in \(G\) (\(N\leq G\)) if, for some modular subgroup \(T\) of \(G\) containing \(A\), \(N\) avoids the pair \((T,A_{mG})\), i.e., \(N\cap T=N\cap A_{mG}\). Using these notions, we give new characterizations of \(p\)-soluble and \(p\)-supersoluble finite groups.

  • Finite Groups with Generalized Subnormal $\mathfrak{F}$-Critical Subgroups

    by S. Wang, A. M. Liu, V. G. Safonov, A. N. Skiba

    Let \(G\) be a finite group and let \(A\) be a subgroup of \(G\). Let \(A_{\operatorname{sn}G}\) be the subgroup of \(A\) generated by all subnormal subgroups of \(G\) contained in \(A\), and let \(A^{\operatorname{sn}G}\) be the intersection of all subnormal subgroups of \(G\) containing \(A\). Let \(N\le G\). Then we say that \(A\) is \(N\)-subnormal in \(G\) if \(N\) avoids every composition factor \(H/K\) of \(G\) between \(A_{\operatorname{sn}G}\) and \(A^{\operatorname{sn}G}\), i.e., \(N\cap H= N\cap K\). In this paper, we give applications of \(N\)-subnormality to the theory of groups with given \(\mathfrak{F}\)-critical subgroups. In particular, using this notion, we give new characterizations of finite solvable groups, metanilpotent groups, and groups with nilpotent derived subgroup \(G'\).

  • Решеточные характеризации $p$-разрешимых и $p$-сверхразрешимых конечных групп

    by А-Мин Лю, Сичэ Ван, В. Г. Сафонов, А. Н. Скиба

    УДК 512.542 MSC: 20D10, 20D30 DOI: 10.21538/0134-4889-2024-30-4-180-187 Работа выполнена при поддержке Национального фонда естественных наук Китая (No. 12101165, No. 12171126) и НФЕНК-БРФФИ (No. 12311530761). Исследования третьего и четвертого авторов выполнены при поддержке Белорусского республиканского фонда фундаментальных исследований (No. Ф24КИ-021). Пусть $G$ — конечная

  • On an application of the lattice of $\sigma$-permutable subgroups of a finite group

    by A. -M. Liu, V. G. Safonov, A. N. Skiba, S. Wang

  • Конечные группы с обобщенно субнормальными $\mathfrak{F}$-критическими подгруппами

    by Sizhe Wang, A. M. Liu, Vasily Grigorevich Safonov, Alexander Nikolaevich Skiba

    Пусть $G$ - конечная группа и $A$ - некоторая ее подгруппа. Пусть $A_{\operatorname{sn}G}$ - подгруппа $A$, порожденная всеми субнормальными подгруппами группы $G$, содержащимися в $A$, и $A^{\operatorname{sn}G}$ - пересечение всех субнормальных подгруппы группы $G$, содержащих $A$. Пусть $N\leqslant G$. Тогда мы говорим, что $A$ $N$-субнормальна в $G$, если $N$ изолирует каждый композиционный фактор $H/K$ группы $G$ между $A_{\operatorname{sn}G}$ и $A^{\operatorname{sn}G}$, т.е. $N\cap H= N\cap K$. В данной работе мы даем приложения $N$-субнормальности в теории групп с заданными $\mathfrak{F}$-критическими подгруппами. В частности, используя это понятие, мы даем новые характеризации конечных разрешимых, метанильпотентных групп и групп с нильпотентной производной подгруппой $G'$. Библиография: 26 названий.

  • Characterizations of some classes of finite soluble groups

    by A-Ming Liu, Zhigang Wang, Vasily G. Safonov, Alexander N. Skiba

  • A criterion for modularity of the subgroup lattice of a finite soluble group

    by A-Ming Liu, Sizhe Wang, Vasily G. Safonov, Alexander N. Skiba

    Let [ ] be a finite group and [ ] the subgroup lattice of [ ]. A subgroup [ ] of [ ] is called: (i) modular in [ ], if [ ] is a modular element (in the sense of Kurosh) of the lattice [ ]; (ii) submodular in [ ] if [ ] has a chain of subgroups [ ], where [ ] is modular in [ ] for all [ ]. If [ ] is a subgroup of [ ], then we denote by [ ] the subgroup of [ ], generated by all of its subgroups that are modular in [ ]. We say that a subgroup [ ] is [ ]-modular in [ ] ([ ]), if for some modular subgroup [ ] of [ ], containing [ ], [ ] avoids the pair [ ], i.e. [ ]. We prove that if [ ] is a soluble finite group and each of its submodular subgroups is [ ]-modular in [ ], where [ ] is the nilpotent residual of [ ], then the lattice [ ] is modular.

  • On 𝜎-permutable subgroups of 𝜎-soluble finite groups

    by Zhigang Wang, A-Ming Liu, Vasily G. Safonov, Alexander N. Skiba

    Let σ = { σ i ∣ i ∈ I } be some partition of the set of all primes and 𝐺 a finite group. Then 𝐺 is said to be 𝜎-full if 𝐺 has a Hall σ i -subgroup for all i ∈ I and 𝜎-primary if 𝐺 is a σ i -group for some 𝑖. In addition, 𝐺 is 𝜎-soluble if every chief factor of 𝐺 is 𝜎-primary and 𝜎-nilpotent if 𝐺 is a direct product of 𝜎-primary groups. We write G N σ for the 𝜎-nilpotent residual of 𝐺, which is the intersection of all normal subgroups 𝑁 of 𝐺 with 𝜎-nilpotent G / N . A subgroup 𝐴 of 𝐺 is said to be 𝜎-permutable in 𝐺 provided 𝐺 is 𝜎-full and 𝐴 permutes with all Hall σ i -subgroups 𝐻 of 𝐺 (that is, A ⁢ H = H ⁢ A ) for all 𝑖. And 𝐴 is 𝜎-subnormal in 𝐺 if there is a subgroup chain A = A 0 ≤ A 1 ≤ ⋯ ≤ A n = G such that either A i − 1 ⁢ ⊴ ⁢ A i or A i / ( A i − 1 ) A i is 𝜎-primary for all i = 1 , … , n . We prove that if 𝐺 is a 𝜎-soluble group, then 𝜎-permutability is a transitive relation in 𝐺 if and only if G N σ ∩ A G = G N σ ∩ A G for every 𝜎-subnormal subgroup 𝐴 of 𝐺.