An example of a planar group whose quasicomponent does not coincide with its component (Q1079671)
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scientific article; zbMATH DE number 3964210
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | An example of a planar group whose quasicomponent does not coincide with its component |
scientific article; zbMATH DE number 3964210 |
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An example of a planar group whose quasicomponent does not coincide with its component (English)
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1985
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The quasicomponent of a point in a topological group is the intersection of all clopen (closed-open) sets containing this point, and the component of a point is the usual maximal connected set containing that point. Treating the plane \({\mathbb{R}}^ 2\) as an abelian topological group (usual topology) with respect to addition, the author constructs a subgroup S of \({\mathbb{R}}^ 2\) and shows that the quasicomponent of the zero element (0,0) in S is isomorphic to the group \({\mathbb{Z}}\) of integers and that the component of (0,0) in S is itself this point thus providing an example of a group in which the quasicomponent of a point is distinct from its component. The subgroup in question is totally disconnected.
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planar group
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quasicomponent
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topological group
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