Generalized Frobenius groups
In this paper the authors develop some results related to a generalization of Frobenius groups due to the reviewer [\textit{A. R. Camina}, Isr. J. Math. 31, 153-160 (1978)]. A finite group G was said to satisfy (F2) if G possesses a proper non-trivial normal subgroup K such that if \(x\in G/K\) and z is in K, then \([x,y]=z\) for some y in G. The reviewer showed that if G satisfies (F2) then either G is a Frobenius group or at least one of G/K or K is a p-group for some prime p. The second author [\textit{I. D. Macdonald}, Isr. J. Math. 40, 350-364 (1981; Zbl 0486.20016)] has studied the structure of such groups when G is a p- group. The authors study the situation when G satisfies (F2) and is neither a Frobenius group nor a p-group. In such a situation either G/K or K is a p-group for some prime p but not both. When this occurs they say that (G,K) is an F2(p) pair. In section 2 they give some new examples of such pairs. The main results are proved in sections 4 and 5. Theorem 4.1. Let (G,K) have F2(p) with K a p-group for some prime p. Let P be a Sylow p- subgroup of G. Assume one of the following conditions holds: (i) G is p- soluble and P/K is Abelian. (ii) G is a p-soluble and P has nilpotency class at most 2. (iii) K is cyclic. Then P is normal in G and (P,K) has (F2). G is a semidirect product \(G=HP\), and HK is a Frobenius group with kernel K. Theorem 5.1. Let (G,K) have F2(p) with G/K a p-group, for some prime p. If a Sylow p-subgroup of G has class at most 2, then G is Frobenius, the Frobenius kernel has index 2 in K and the Frobenius complement is the quaternion group of order 8. In particular \(p=2\) and \(| G/K| =4\). - These two results go a lot further than previous work but leave a lot of interesting unanswered questions.
scientific article; zbMATH DE number 3845827