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On the closure of the diagonal of a \(T_1\)-space - MaRDI portal

On the closure of the diagonal of a \(T_1\)-space (Q941438)

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On the closure of the diagonal of a \(T_1\)-space
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    On the closure of the diagonal of a \(T_1\)-space (English)
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    1 September 2008
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    Let \(X\) be a topological space. The closure of \(\Delta=\{(x, x): x\in X\}\) in \(X\times X\) is a symmetric relation on \(X\). The equivalence relations on an infinite set that arise as the closure of the diagonal with respect to a \(T_{1}\)-topology are characterized.
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    diagonal
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    equivalence relation
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    separation
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    \(T_{1}\)-space
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