Projective Representations, Abelian F-Groups, and Central Extensions
نویسندگان
چکیده
منابع مشابه
Generic Central Extensions and Projective Representations of Finite Groups
Any free presentation for the finite group G determines a central extension (R, F ) for G having the projective lifting property for G over any field k. The irreducible representations of F which arise as lifts of irreducible projective representations of G are investigated by considering the structure of the group algebra kF , which is greatly influenced by the fact that the set of torsion ele...
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Let $pounds$ be the category of locally compact abelian groups and $A,Cin pounds$. In this paper, we define component extensions of $A$ by $C$ and show that the set of all component extensions of $A$ by $C$ forms a subgroup of $Ext(C,A)$ whenever $A$ is a connected group. We establish conditions under which the component extensions split and determine LCA groups which are component projective. ...
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Suppose G is a subgroup of the reduced abelian p-group A. The following two dual results are proved: (∗) If A/G is countable and G is an almost totally projective group, then A is an almost totally projective group. (∗∗) If G is countable and nice in A such that A/G is an almost totally projective group, then A is an almost totally projective group. These results somewhat strengthen theorems du...
متن کاملBilinear Maps and Central Extensions of Abelian Groups
The main result of this paper is that every nilpotent group of class at most two may be embedded into a central extension of abelian groups, in which the associated cocycle is bilinear (definitions are recalled in Section 1). The result is related to a paper of N.J.S. Hughes (see [2]), in which he establishes a one to one correspondence between the equivalence classes of central extensions of a...
متن کاملon component extensions locally compact abelian groups
let $pounds$ be the category of locally compact abelian groups and $a,cin pounds$. in this paper, we define component extensions of $a$ by $c$ and show that the set of all component extensions of $a$ by $c$ forms a subgroup of $ext(c,a)$ whenever $a$ is a connected group. we establish conditions under which the component extensions split and determine lca groups which are component projective. ...
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ژورنال
عنوان ژورنال: Journal of Algebra
سال: 1993
ISSN: 0021-8693
DOI: 10.1006/jabr.1993.1186