Partial order on a family of \(k\)-subsets of a linearly ordered set (Q2368930)

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Partial order on a family of \(k\)-subsets of a linearly ordered set
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    Partial order on a family of \(k\)-subsets of a linearly ordered set (English)
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    28 April 2006
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    For \(k\)-subsets \(A\) and \(B\) of the rationals, define \(A\, Rn\, B\) if \(a R b\) holds for at least \(n\) ordered pairs \((a, b)\) in \(A\, \times \, B\), where \(k\) and \(n\) are integers bounded between \(1\) and \(kk\). The paper shows that the relation \(Rn\) is transitive if and only if \(k(k - 1) + 1\) is less than \(n + 1\), and that there is a cyclic sequence of \(k\)-subsets of the rationals if and only if \(n\) is bounded between \(1\) and \(kk - (k + 1)(k + 1)/4\). The paper also considers the length of such cyclic sequences.
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    transitivity
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    cyclic sequence
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    acyclic digraph
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