Geodesic
On GL2 of a Local Ring in Which 2 is Not a Unit
Canadian mathematical bulletin, Tome 30 (1987) no. 2, pp. 165-176

Voir la notice de l'article provenant de la source Cambridge University Press

Let A be a local ring with maximal ideal m, let N(m ) be the order of the residue field A/m and let N be a subgroup of GLn (A) which is normalized by SLn(A). It follows from results of Klingenberg that N is normal in GLn(A) when n ≥ 3 or . Results of Lacroix show that this is also true when n = 2 and N(m) = 3, provided that N∩2(A) ≠ SL2(A)'.The principal aim of this paper is to provide examples of non-normal subgroups of GL2(A) which are normalized by SL2(A). In the process we extend results of Lacroix and Levesque on GL2(A)-normalized subgroups of GL2(A), where 2 ∊ m and N(m) > 2.
DOI : 10.4153/CMB-1987-024-6
Mots-clés : 20 H 05 
Mason, A. W. On GL2 of a Local Ring in Which 2 is Not a Unit. Canadian mathematical bulletin, Tome 30 (1987) no. 2, pp. 165-176. doi: 10.4153/CMB-1987-024-6
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