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JOURNALS // Zapiski Nauchnykh Seminarov POMI // Archive

Zap. Nauchn. Sem. POMI, 2017 Volume 455, Pages 122–129 (Mi znsl6411)

This article is cited in 4 papers

The normalizer of the elementary linear group of a module arising under extension of the base ring

N. H. T. Nhat, T. N. Hoi

Faculty of Mathematics and Computer Science, University of Science, VNU-HCM, 227 Nguyen Van Cu Str., Dist. 5, Ho Chi Minh City, Vietnam

Abstract: Let $S$ be a commutative ring with $1$ and $R$ a unital subring. Let $M$ be a free $S$-module of rank $n\geq3$. In [1], V. A. Koibaev described the normalizer of $\operatorname{Aut}_S(M)$ in the group $\operatorname{Aut}_R(M)$. In this paper, we show that in $\operatorname{Aut}_R(M)$ the normalizer of the elementary linear group $E_\mathfrak B(M)$ coincides with the one of $\operatorname{Aut}_S(M)$, namely, $N_{\operatorname{Aut}_R(M)}(E_\mathfrak B(M))=\operatorname{Aut}(S/R)\ltimes\operatorname{Aut}_S(M)$. If $S$ is free of rank $m$ as an $R$-module, then $N_{\operatorname{GL}(mn,R)}(E(n,S))=\operatorname{Aut}(S/R)\ltimes\operatorname{GL}(n,S)$, moreover, for any proper ideal $A$ of $R$, we have
$$ N_{\operatorname{GL}(mn, R)}(E(n,S)E(mn,R,A))=\rho_A^{-1}(N_{\operatorname{GL}(mn,R/A)}(E(n,S/SA))). $$


Key words and phrases: automorphism group of a module, lattice of subgroups, ring extension subgroup, normalizer.

UDC: 512.743

Received: 05.04.2017

Language: English


 English version:
Journal of Mathematical Sciences (New York), 2018, 234:2, 197–202


© Steklov Math. Inst. of RAS, 2024