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On set systems with a threshold property - MaRDI portal

On set systems with a threshold property (Q856857)

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scientific article; zbMATH DE number 5080054
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On set systems with a threshold property
scientific article; zbMATH DE number 5080054

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    On set systems with a threshold property (English)
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    14 December 2006
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    For integers \(1 < t < k < n\) the set system \(\mathcal F\) on \([n]\) has the \((k,t)\)-threshold property if every \(k\)-subset of \([n]\) contains at least \(t\) sets from \(\mathcal F\) while every \((k-1)\)-subset of \([n]\) contains less than \(t\) sets from \(\mathcal F.\) The minimal cardinality of such a set system is denoted by \(m(n,k,t).\) This papers determines \(m(n,k,t)\) exactly for large enough \(n.\) It also shows that \(m(n,k,2)=(1+o(1))T_{(k-1)}(n,k,2)\) where the last item on the RHS is the generalized Turán number.
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    extremal problems
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    packing
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    Turán's theorem
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