Covering sets by subsets (Q797580)
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scientific article; zbMATH DE number 3867335
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | Covering sets by subsets |
scientific article; zbMATH DE number 3867335 |
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Covering sets by subsets (English)
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1984
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Let to every element x of a finite set M be associated some nonempty subset M(x) of M in such a way that the implication \(y\in M(x)\Rightarrow x\in M(y)\) is fulfilled. We prove two upper estimations for the least number of sets M(x) which are necessary to cover M. Several applications to number theory are presented.
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subsets
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covering number
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