On a topological invariant of finite topological spaces and enumerations (Q1202791)
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scientific article; zbMATH DE number 109329
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | On a topological invariant of finite topological spaces and enumerations |
scientific article; zbMATH DE number 109329 |
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On a topological invariant of finite topological spaces and enumerations (English)
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22 February 1993
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For a reflexive idempotent \(n\times n\) Boolean matrix \(A\), the author defines \(\alpha(A)\) as the number of \((n+1)\times (n+1)\) reflexive idempotents whose last \(n\) rows and columns equal \(A\). He derives a number of formulas for \(\alpha(A)\). Such matrices are in \(1-1\) correspondence with topologies on finite sets.
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enumeration of poset
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enumeration of topology
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idempotent Boolean matrix
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