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JOURNALS // Problemy Fiziki, Matematiki i Tekhniki (Problems of Physics, Mathematics and Technics) // Archive

PFMT, 2018 Issue 4(37), Pages 90–97 (Mi pfmt610)

This article is cited in 1 paper

MATHEMATICS

On the problem of Doerk and Hawkes for locally normal Fitting classes

A. V. Martsinkevich

P.M. Masherov Vitebsk State University

Abstract: Let $\mathfrak{F}$ be a non-empty class of finite groups. A Fitting class $\mathfrak{F}$ is said to be $\mathfrak{X}$-normal or normal in a class of finite groups $\mathfrak{X}$ if $\mathfrak{F}\subseteq\mathfrak{X}$ and for all $G\in\mathfrak{X}$ an $\mathfrak{F}$-radical of $G$ is $\mathfrak{F}$-maximal in $G$. If $\mathfrak{X}$ is a class of all soluble finite groups, then $\mathfrak{X}$-normal Fitting class is called normal. In the theory of normal Fitting classes the problem of Doerk and Hawkes is well known. Let $\mathfrak{X}$ be a Fitting class and $\mathfrak{X}=\mathfrak{X}^2$. Is the intersection of two non-trivial $\mathfrak{X}$-normal Fitting classes always non-trivial $\mathfrak{X}$-normal Fitting class? In this paper a positive answer to this question without the requirement that $\mathfrak{X}=\mathfrak{X}^2$ for the case of arbitrary family of non-trivial $\mathfrak{X}$-normal Fischer classes partially soluble groups, where $\mathfrak{X}$ is a Fischer class such, that $\mathfrak{N}_p\mathfrak{X}=\mathfrak{X}$ for some prime $p$ is given.

Keywords: Fitting class, $\mathfrak{X}$-normal Fitting class, $\mathfrak{F}$-radical, intersection of Fitting classes.

UDC: 512.542

Received: 23.07.2018



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