scholarly journals ON ONE OF HERSTEIN'S CONJECTURES

2009 ◽  
Vol 12 (11) ◽  
pp. 5-10
Author(s):  
Thin Van Nguyen ◽  
Hai Xuan Bui

Let D be a division ring with the center F. We say that N is a subgroup of D with understanding that N is in fact a subgroup of the multiplicative group D* of D. In this note we disscus the conjecture which was posed by Herstein in 1978 [2, Conjecture 3]: If N is a subnormal subgroup of D which is radical over F, then N is contained in F. In his paper, Herstein himself showed that the conjecture is true if N is a finite subnormal subgroup of D. However, it is not proven for the general cases. In this note, we establish some properties of subnormal subgroups in division rings which could give some information in the direction of verifying this longstanding conjecture. In particular, it is shown that the conjecture is true for locally centrally finite division rings.

1963 ◽  
Vol 15 ◽  
pp. 80-83 ◽  
Author(s):  
I. N. Herstein ◽  
W. R. Scott

Let K be a division ring. A subgroup H of the multiplicative group K′ of K is subnormal if there is a finite sequence (H = A0, A1, . . . , An = K′) of subgroups of K′ such that each Ai is a normal subgroup of Ai+1. It is known (2, 3) that if H is a subdivision ring of K such that H′ is subnormal in K′, then either H = K or H is in the centre Z(K) of K.


Author(s):  
M. H. Bien ◽  
M. Ramezan-Nassab

In this paper, we study some algebras [Formula: see text] whose unit groups [Formula: see text] or subnormal subgroups of [Formula: see text] are (generalized) Engel. For example, we show that any generalized Engel subnormal subgroup of the multiplicative group of division rings with uncountable centers is central. Some of algebraic structures of Engel subnormal subgroups of the unit groups of skew group algebras over locally finite or torsion groups are also investigated.


2016 ◽  
Vol 15 (03) ◽  
pp. 1650050 ◽  
Author(s):  
Bui Xuan Hai ◽  
Nguyen Anh Tu

Let [Formula: see text] be a division ring. In this paper, we investigate properties of subgroups of an arbitrary subnormal subgroup of the multiplicative group [Formula: see text] of [Formula: see text]. The new obtained results generalize some previous results on subgroups of [Formula: see text].


1978 ◽  
Vol 30 (01) ◽  
pp. 161-163 ◽  
Author(s):  
Gary R. Greenfield

Let D be a division algebra and let D* denote the multiplicative group of nonzero elements of D. In [3] Herstein and Scott asked whether any subnormal subgroup of D* must be normal in D*. Our purpose here is to show that division algebras over certain p-local fields do not satisfy such a “subnormal property”.


2009 ◽  
Vol 12 (17) ◽  
pp. 5-11
Author(s):  
Bien Hoang Mai ◽  
Hai Xuan Bui

Let D be a division ring with the center F and suppose that D* is the multiplicative group of D. D is called centrally finite if D is a finite dimensional vector space over F and D is locally centrally finite if every finite subset of D generates over F a division subring which is a finite dimensional vector space over F. We say that D is a linear division ring if every finite subset of D generates over Fa centrally finite division subring. It is obvious that every locally centrally finite division ring is linear. In this report we show that the inverse is not true by giving an example of a linear division ring which is not locally centrally finite. Further, we give some properties of subgroups in linear division rings. In particular, we show that every finitely generated subnormal subgroup in a linear ring is central. An interesting corollary is obtained as the following: If D is a linear division ring and D* is finitely generated, then D is a finite field.


2005 ◽  
Vol 15 (01) ◽  
pp. 15-36 ◽  
Author(s):  
VITOR O. FERREIRA ◽  
JAIRO Z. GONÇALVES ◽  
ARNALDO MANDEL

Let D be a division ring with an involution and characteristic different from 2. Then, up to a few exceptions, D contains a pair of symmetric elements freely generating a free subgroup of its multiplicative group provided that (a) it is finite-dimensional and the center has a finite sufficiently large transcendence degree over the prime field, or (b) the center is uncountable, but not algebraically closed in D. Under conditions (a), if the involution is of the first kind, it is also shown that the unitary subgroup of the multiplicative group of D contains a free subgroup, with one exception. The methods developed are also used to exhibit free subgroups in the multiplicative group of a finite-dimensional division ring provided the center has a sufficiently large transcendence degree over its prime field.


1973 ◽  
Vol 25 (4) ◽  
pp. 881-887 ◽  
Author(s):  
E. D. Elgethun

In [8] I. N. Herstein conjectured that all the finite odd order sub-groups of the multiplicative group in a division ring are cyclic. This conjecture was proved false in general by S. A. Amitsur in [1]. In his paper Amitsur classifies all finite groups which can appear as a multiplicative subgroup of a division ring. Let D be a division ring with prime field k and let G be a finite group isomorphic to a multiplicative subgroup of D.


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