Rings with Fixed-Point-Free Group Actions

1973 ◽  
Vol s3-27 (1) ◽  
pp. 69-87 ◽  
Author(s):  
G. M. Bergman ◽  
I. M. Isaacs
2015 ◽  
Vol 27 (3) ◽  
Author(s):  
Nansen Petrosyan

AbstractUsing fixed-point-free group actions, we set up a scheme to define nested classes of groups indexed over ordinals. Restricting to cellular actions on CW-complexes, we find new classes of groups as well as new characterizations for some well-known classes. We extend some of the properties of the cohomological dimension of a group to groups with jump (co)homology and study their implications to cellular actions on finite dimensional CW-complexes that satisfy a quite general homological condition.


1991 ◽  
Vol 06 (07) ◽  
pp. 591-603
Author(s):  
B.R. GREENE ◽  
M.R. PLESSER ◽  
EDMOND RUSJAN ◽  
XING-MIN WANG

We study the construction of (2, 0) theories from orbifolds of N=2 minimal superconformal string compactifications with non-trivial Wilson loops. In particular, we exploit the connection between geometrical and exactly soluble string vacua to arrive at a mean of analyzing Calabi-Yau orbifolds containing ‘Wilson loops’ associated with non-free group actions, breaking the E6 gauge symmetry of the model as well the ‘shadow’ E8 gauge symmetry group. We apply our results to recently proposed three generation constructions of this sort and find spectra which differ from previous claims and which possess exceptionally desirable phenomenological properties.


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