scholarly journals A note on Abelian group extensions

1962 ◽  
Vol 12 (4) ◽  
pp. 1401-1403 ◽  
Author(s):  
Ronald Nunke
1973 ◽  
Vol 15 (4) ◽  
pp. 428-429 ◽  
Author(s):  
G. J. Hauptfleisch

If A, B, H, K are abelian group and φ: A → H and ψ: B → K are epimorphisms, then a given central group extension G of H by K is not necessarily a homomorphic image of a group extension of A by B. Take for instance A = Z(2), B = Z ⊕ Z, H = Z(2), K = V4 (Klein's fourgroup). Then the dihedral group D8 is a central extension of H by K but it is not a homomorphic image of Z ⊕ Z ⊕ Z(2), the only group extension of A by the free group B.


1975 ◽  
Vol 78 (3) ◽  
pp. 357-368 ◽  
Author(s):  
B. A. F. Wehrfritz

This paper is devoted to the construction of faithful representations of the automorphism group and the holomorph of an extension of an abelian group by some other group, the representations here being homomorphisms into certain restricted parts of the automorphism groups of smallish abelian groups. We apply these to two very specific cases, namely to finitely generated metabelian groups and to certain soluble groups of finite rank. We describe the applications first.


2010 ◽  
Vol 324 (4) ◽  
pp. 820-830 ◽  
Author(s):  
I.B.S. Passi ◽  
Mahender Singh ◽  
Manoj K. Yadav

2021 ◽  
Author(s):  
Alexander I. Suciu

Abstract We study the integral, rational, and modular Alexander invariants, as well as the cohomology jump loci of groups arising as extensions with trivial algebraic monodromy. Our focus is on extensions of the form 1→K→G→Q→1, where Q is an abelian group acting trivially on H1(K;ℤ), with suitable modifications in the rational and mod-p settings. We find a tight relationship between the Alexander invariants, the characteristic varieties, and the resonance varieties of the groups K and G. This leads to an inequality between the respective Chen ranks, which becomes an equality in degrees greater than 1 for split extensions.


1979 ◽  
Vol 54 (1) ◽  
pp. 440-457 ◽  
Author(s):  
Paul C. Eklof ◽  
Martin Huber

2010 ◽  
Vol 119 (1) ◽  
pp. 1-22
Author(s):  
Chris Dodd ◽  
Phakawa Jeasakul ◽  
Anne Jirapattanakul ◽  
Daniel M. Kane ◽  
Becky Robinson ◽  
...  

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