scholarly journals Generic central extensions and projective representations of finite groups

2001 ◽  
Vol 5 (6) ◽  
pp. 129-146 ◽  
Author(s):  
Rachel Quinlan
1979 ◽  
Vol 86 (3) ◽  
pp. 413-419 ◽  
Author(s):  
J. F. Humphreys

Let G bea finite group, let C1, …, Cn be the cyclic subgroups of G and let 1i be the identity linear character of Ci (1 ≤ i ≤ n). It is a well-known result of Artin ((l), 39·1) that a character x of a linear representation of G over the rational numbers may be writtenwhere a1, …, an are integers. In this note, we establish an analogue of this result for characters of projective representations over the rational numbers.


2004 ◽  
Vol 69 (1) ◽  
pp. 161-171 ◽  
Author(s):  
Emanuele Pacifici

We prove that, given a quasi-primitive complex representation D for a finite group G, the possible ways of decomposing D as an inner tensor product of two projective representations of G are parametrised in terms of the group structure of G. More explicitly, we construct a bijection between the set of such decompositions and a particular interval in the lattice of normal subgroups of G.


Author(s):  
P. N. Hoffmann ◽  
J. F. Humphreys

The projective representations of a finite group G over a field K are divided into sets, each parametrized by an element of the group H2(G, Kx). The latter is the Schur multiplier M(G) when K = ℂ.


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