More countably recognizable classes of groups
نویسندگان
چکیده
منابع مشابه
Finite Groups Have More Conjugacy Classes
We prove that for every > 0 there exists a δ > 0 so that every group of order n ≥ 3 has at least δ log2 n/(log2 log2 n) 3+ conjugacy classes. This sharpens earlier results of Pyber and Keller. Bertram speculates whether it is true that every finite group of order n has more than log3 n conjugacy classes. We answer Bertram’s question in the affirmative for groups with a trivial solvable radical.
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We describe soluble groups in which the set of all subgroups is countable and show that locally (soluble-byfinite) groups with this property are soluble-by-finite. Further, we construct a nilpotent group with uncountably many subgroups in which the set of all abelian subgroups is countable.
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In his paper ”Finite groups have many conjugacy classes” (J. London Math. Soc (2) 46 (1992), 239-249), L. Pyber proved the to date best general lower bounds for the number of conjugacy classes of a finite group in terms of the order of the group. In this paper we strengthen the main results in Pyber’s paper.
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ژورنال
عنوان ژورنال: Journal of Pure and Applied Algebra
سال: 2009
ISSN: 0022-4049
DOI: 10.1016/j.jpaa.2008.11.030