Groups and actions in transformation semigroups
Groups and actions in transformation semigroups
复制标题
变换半群中的群和动作
DOI:
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发表时间:
1998
期刊:
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通讯作者:
N. Ruškuc
中科院分区:
文献类型:
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作者:
S. Linton;G. Pfeiffer;E. Robertson;N. Ruškuc
Abstract. Let
$S$ be a transformation semigroup of degree
$n$. To each element
$sin S$ we associate a permutation group
$G_R(s)$ acting on the image of
$s$, and we find a natural generating set for this group. It turns out that the
$mathcal{R}$-class of
$s$ is a disjoint union of certain sets, each having size equal to the size of
$G_R(s)$. As a consequence, we show that two
$mathcal{R}$-classes containing elements with equal images have the same size, even if they do not belong to the same
$mathcal{D}$-class. By a certain duality process we associate to
$s$ another permutation group
$G_L(s)$ on the image of
$s$, and prove analogous results for the
$mathcal{L}$-class of
$S$. Finally we prove that the Schützenberger group of the
$mathcal{H}$-class of
$s$ is isomorphic to the intersection of
$G_R(s)$ and
$G_L(s)$. The results of this paper can also be applied in new algorithms for investigating transformation semigroups, which will be described in a forthcoming paper.