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Estimates of the p-length of invariant subgroups of a finite group. (Russian) Zbl 0615.20014

Let G be a finite group, p a prime number and \(H\trianglelefteq G\). The author defines \(m_ p(G-H)\) as the least integer n for which every maximal chain of subgroups whose orders are multiples of p and which do not contain H (a chain consisting of n such subgroups) such a chain necessarily contains a proper modular subgroup of G. If there is not any such subgroup, then \(m_ p(G-H)=1\). If the word ”modular” in this definition is substituted by ”p-subnormal” then it defines a function \(h_ p(G-H)\). The generalized p-length \(L_ p(G)\) of an arbitrary finite group G was introduced and studied by L. A. Shemetkov [in Mat. Sb., Nov. Ser. 72(114), 97-107 (1967; Zbl 0179.324)] (for a p- solvable group G \(L_ p(G)\) coincides with the usual p-length \(l_ p(G)\) of Hall and Higman). Theorem 1 states that always \(L_ p(H)\leq m_ p(G-H)\) and theorem 2 that \(L_ p(H)\leq h_ p(G-H)\).
Reviewer: E.I.Khukhro

MSC:

20D30 Series and lattices of subgroups
20D35 Subnormal subgroups of abstract finite groups
20D60 Arithmetic and combinatorial problems involving abstract finite groups
20D10 Finite solvable groups, theory of formations, Schunck classes, Fitting classes, \(\pi\)-length, ranks

Citations:

Zbl 0179.324