Closure functions on the set of positive integers (Q1918995)
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scientific article; zbMATH DE number 908251
| Language | Label | Description | Also known as |
|---|---|---|---|
| English | Closure functions on the set of positive integers |
scientific article; zbMATH DE number 908251 |
Statements
Closure functions on the set of positive integers (English)
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23 July 1996
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The following question, raised by P. C. Hammer in 1960, is answered: Let \(M\) be the set of all positive integers, \(h\) the closure function under multiplication defined on the power set of \(M\) and \(c\) the complementation function. Do \(h\) and \(c\) generate exactly 14 distinct functions by composition in any order? Different types of sets which yield 14 distinct sets in the set of positive integers have also been found.
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\(K\)-sets
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algebraic boundary
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closure function
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complementation function
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