The Complete Reducibility of Locally Completely Reducible Finitary Linear Groups

1997 ◽  
Vol 29 (2) ◽  
pp. 173-176 ◽  
Author(s):  
B. A. F. Wehrfritz
2020 ◽  
Vol 8 ◽  
Author(s):  
MAIKE GRUCHOT ◽  
ALASTAIR LITTERICK ◽  
GERHARD RÖHRLE

We study a relative variant of Serre’s notion of $G$ -complete reducibility for a reductive algebraic group $G$ . We let $K$ be a reductive subgroup of $G$ , and consider subgroups of $G$ that normalize the identity component $K^{\circ }$ . We show that such a subgroup is relatively $G$ -completely reducible with respect to $K$ if and only if its image in the automorphism group of $K^{\circ }$ is completely reducible. This allows us to generalize a number of fundamental results from the absolute to the relative setting. We also derive analogous results for Lie subalgebras of the Lie algebra of $G$ , as well as ‘rational’ versions over nonalgebraically closed fields.


2013 ◽  
Vol 23 (04) ◽  
pp. 915-941 ◽  
Author(s):  
DOMINIQUE PERRIN

We study the family of rational sets of words, called completely reducible and which are such that the syntactic representation of their characteristic series is completely reducible. This family contains, by a result of Reutenauer, the submonoids generated by bifix codes and, by a result of Berstel and Reutenauer, the cyclic sets. We study the closure properties of this family. We prove a result on linear representations of monoids which gives a generalization of the result concerning the complete reducibility of the submonoid generated by a bifix code to sets called birecurrent. We also give a new proof of the result concerning cyclic sets.


1993 ◽  
Vol s2-47 (1) ◽  
pp. 31-40 ◽  
Author(s):  
Ulrich Meierfrankenfeld ◽  
Richard E. Phillips ◽  
Orazio Puglisi

1993 ◽  
Vol s2-48 (1) ◽  
pp. 59-76 ◽  
Author(s):  
Felix Leinen ◽  
Orazio Puglisi

2000 ◽  
Vol 43 (1) ◽  
pp. 27-41
Author(s):  
B. A. F. Wehrfritz

AbstractWe consider faithful finitary linear representations of (generalized) wreath products A wrΩH of groups A by H over (potentially) infinite-dimensional vector spaces, having previously considered completely reducible such representations in an earlier paper. The simpler the structure of A the more complex, it seems, these representations can become. If A has no non-trivial abelian normal subgroups, the conditions we present are both necessary and sufficient. They imply, for example, that for such an A, if there exists such a representation of the standard wreath product A wr H of infinite dimension, then there already exists one of finite dimension.


2012 ◽  
Vol 195 (2) ◽  
pp. 745-772 ◽  
Author(s):  
Silvio Dolfi ◽  
Robert Guralnick ◽  
Cheryl E. Praeger ◽  
Pablo Spiga

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