Some generalizations of property \(B\) and the splitting property (Q1306741)

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scientific article; zbMATH DE number 1347989
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Some generalizations of property \(B\) and the splitting property
scientific article; zbMATH DE number 1347989

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    Some generalizations of property \(B\) and the splitting property (English)
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    23 February 2000
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    The following theorem is proved: Let \({\mathcal A}_1,\dots, {\mathcal A}_k\) \((k\geq 2)\) be set systems on the finite set \(X\). Assume that for every \(i= 1,\dots, k\) and for all set systems \({\mathcal A}_{j_1},\dots,{\mathcal A}_{j_i}\) \((1\leq j_1<\cdots< j_i\leq k)\) we have \(|A_1\cap\cdots\cap A_i|\not\in \{1,\dots, i-1\}\) for all \(A_l\in{\mathcal A}_{j_l}\) with \(l= 1,\dots, i\). Then there is a \(k\)-partition \(X_1\cup\cdots \cup X_k= X\) such that \(X_i\cap A\) is non-empty for every \(i= 1,\dots, k\) and for all \(A\in{\mathcal A}_i\). The author conjectures that the intersection condition can be replaced by \(|A_1\cap\cdots\cap A_i|\neq i-1\). Variants are discussed.
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    splitting property
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    property B
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    generator system
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    set systems
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