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JOURNALS // Vladikavkazskii Matematicheskii Zhurnal // Archive

Vladikavkaz. Mat. Zh., 2017 Volume 19, Number 1, Pages 26–29 (Mi vmj604)

Cyclical elementary nets

N. A. Dzhusoeva, R. Y. Dryaeva

North Ossetian State University after Kosta Levanovich Khetagurov, Vladikavkaz

Abstract: Let $R$ be a commutative ring with the unit and $n\in\mathbb{N}$. A set $\sigma = (\sigma_{ij})$, $1\leqslant{i, j} \leqslant{n},$ of additive subgroups of the ring $R$ is a net over $R$ of order $n$, if $ \sigma_{ir} \sigma_{rj} \subseteq{\sigma_{ij}} $ for all $1\leqslant i, r, j\leqslant n$. A net which doesn't contain the diagonal is called an elementary net. An elementary net $\sigma = (\sigma_{ij}), 1\leqslant{i\neq{j} \leqslant{n}}$, is complemented, if for some additive subgroups $\sigma_{ii}$ of $R$ the set $\sigma = (\sigma_{ij}), 1\leqslant{i, j} \leqslant{n}$ is a full net. An elementary net $\sigma$ is called closed, if the elementary group $ E(\sigma) = \langle t_{ij}(\alpha) : \alpha\in \sigma_{ij}, 1\leqslant{i\neq{j}} \leqslant{n}\rangle $ doesn't contain elementary transvections. It is proved that the cyclic elementary odd-order nets are complemented. In particular, all such nets are closed. It is also shown that for every odd $n\in\mathbb{N}$ there exists an elementary cyclic net which is not complemented.

Key words: intermediate subgroup, non-split maximal torus, net, cyclic net, net group, elementary group, transvection.

UDC: 519.46

Received: 14.03.2016



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