共查询到20条相似文献,搜索用时 15 毫秒
1.
William Kerby 《Aequationes Mathematicae》1991,41(1):187-191
Summary Nearfields of rank 2 over their kernel which are not Dickson nearfields have recently been constructed by H. Zassenhaus. Here it is shown that KT-nearfields of rank 2 over their kernels and of characteristic 2 are necessarily Dickson nearfields which are coupled to quadratic field extensions and their Dickson group is isomorphic to 2. Using results of Gröger one obtains all KT-nearfields of rank 2 over the field of rational numbers. 相似文献
2.
William Kerby 《Aequationes Mathematicae》1986,31(1):247-252
3.
Aequationes mathematicae - 相似文献
4.
In this note, we construct an example of a locally compact abelian group
G = C × D (where C is a compact group and D
is a discrete group) and a closed pure subgroup of G
having nonpure annihilator in the Pontrjagin dual $\hat{G}$, answering a question
raised by Hartman and Hulanicki. A simple proof of the following result is given:
Suppose ${\frak K}$ is a class of locally compact abelian groups such
that $G \in {\frak K}$ implies that $\hat{G} \in {\frak K}$ and
nG is closed in G for each positive integer
n. If H is a
closed subgroup of a group $G \in {\frak K}$, then
H is topologically pure in
G exactly if the annihilator of
H is topologically pure in
$\hat{G}$. This result extends a theorem of Hartman and Hulanicki.Received: 4 April 2002 相似文献
5.
The equivalence (or weak equivalence) classes of orientation-preserving free actions of a finite group G on an orientable three-dimensional handlebody of genus g?1 can be enumerated in terms of sets of generators of G. They correspond to the equivalence classes of generating n-vectors of elements of G, where n=1+(g−1)/|G|, under Nielsen equivalence (or weak Nielsen equivalence). For Abelian and dihedral G, this allows a complete determination of the equivalence and weak equivalence classes of actions for all genera. Additional information is obtained for other classes of groups. For all G, there is only one equivalence class of actions on the genus g handlebody if g is at least 1+?(G)|G|, where ?(G) is the maximal length of a chain of subgroups of G. There is a stabilization process that sends an equivalence class of actions to an equivalence class of actions on a higher genus, and some results about its effects are obtained. 相似文献
6.
7.
On commuting automorphisms of groups 总被引:4,自引:0,他引:4
This paper examines group automorphisms for which each element commutes with its image. These automorphisms do not necessarily
form a subgroup of the automorphism group, but have a number of interesting properties, close to those of central automorphisms.
Research of the first named author was supported by Grant SM 177 from Kuwait University Research Administration. 相似文献
8.
Nobuo Aoki 《Topology and its Applications》1985,20(1):1-15
It is proved, by using topological properties, that when a group automorphism of a locally compact totally disconnected group is ergodic under the Haar measure, the group is compact. The result is an answer for Halmos's question that has remained open for the totally disconnected case. 相似文献
9.
Lydia Außenhofer 《Mathematische Zeitschrift》2007,257(2):239-250
For a topological group G, we denote by G
a
the arc component of the neutral element and by the character group of G, i.e. the group of all continuous homomorphisms from G into T. We prove the following theorem: Let G be a connected locally compact abelian group and let be the embedding. Then is a topological isomorphism. In particular, the character group of the arc component of a compact abelian group is discrete.
Some conclusions will be drawn. 相似文献
10.
Manfred Droste 《Order》1988,5(3):261-273
We show that any lattice-ordered group (l-group) G can be l-embedded into continuously many l-groups H
i
which are pairwise elementarily inequivalent both as groups and as lattices with constant e. Our groups H
i
can be distinguished by group-theoretical first-order properties which are induced by lattice-theoretically nice properties of their normal subgroup lattices. Moreover, they can be taken to be 2-transitive automorphism groups A(S
i
) of infinite linearly ordered sets (S
i
, ) such that each group A(S
i
) has only inner automorphisms. We also show that any countable l-group G can be l-embedded into a countable l-group H whose normal subgroup lattice is isomorphic to the lattice of all ideals of the countable dense Boolean algebra B. 相似文献
11.
12.
We construct a full class of nilpotent groups of class 2 of an arbitrary infinite
cardinality . Their centers, commutator subgroups and factors modulo the center will be the
same and a homogeneous direct sum of a group of rank 1 or 2. Their automorphism groups will
coincide and the factor group modulo the stabilizer could be an arbitrary group of size $\leqq$ . 相似文献
13.
14.
15.
Jochen Koenigsmann 《manuscripta mathematica》1998,95(1):251-271
Letp be a prime >2, letF be a field of characteristic ≠p containing a primitivep-th root of unity and letG
F
(p) be the Galois group of the maximal Galois-p-extension ofF. Ifrk G
F
(p)≤4 thenG
F
(p) is a free pro-p product of metabelian groups orG
F
(p) is a Demuškin group of rank 4. 相似文献
16.
M. Rovinsky 《Selecta Mathematica, New Series》2005,11(3-4):491-522
Let L be the function field of a projective space
over an algebraically closed field k of characteristic zero, and H be the group of projective transformations. An H-sheaf
on
is a collection of isomorphisms
for each g ∈ H satisfying the chain rule.
We construct, for any n > 1, a fully faithful functor from the category of finite-dimensional L-semilinear representations of H extendable to the semigroup End(L/k) to the category of coherent H-sheaves on
The paper is motivated by a study of admissible representations of the automorphism group G of an algebraically closed extension of k of countable transcendence degree undertaken in [4]. The semigroup End(L/k) is considered as a subquotient of G, hence the condition on extendability.
In the appendix it is shown that, if
is either H, or a bigger subgroup in the Cremona group (generated by H and a certain pair of involutions), then any semilinear
of degree one is an integral L-tensor power of
It is also shown that this bigger subgroup has no non-trivial representations of finite degree if n > 1. 相似文献
17.
18.
W. Nöbauer 《Periodica Mathematica Hungarica》1986,17(1):37-44
L. Rédei has introduced in 1946 a class of rational functions over finite fields of orderp
t
–p being an odd prime — and has proved some interesting results on permutations which are induced by these functions. Recently, similar results have been found for factor rings of the integers of orderp
t
; moreover, these functions have been applied to construct public key cryptosystems. In this paper we consider functions of Rédei type over finite fields and factor rings of the integers of order 2
t
. We show that most of the results for oddp also hold in this case. 相似文献
19.
20.
This paper forms a portion of the Ph.D dissertation written by the first author under the supervision of the second author, and submitted to the University of Baghdad in 1990. 相似文献