Double Derangement Permutations
| Autor: | Madjid Mirzavaziri, Kamyar Mirzavaziri, Pooya Daneshmand |
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| Rok vydání: | 2016 |
| Předmět: | |
| Zdroj: | Open Journal of Discrete Mathematics. :99-104 |
| ISSN: | 2161-7643 2161-7635 |
| DOI: | 10.4236/ojdm.2016.62010 |
| Popis: | Let n be a positive integer. A permutation a of the symmetric group of permutations of is called a derangement if for each . Suppose that x and y are two arbitrary permutations of . We say that a permutation a is a double derangement with respect to x and y if and for each . In this paper, we give an explicit formula for , the number of double derangements with respect to x and y. Let and let and be two subsets of with and . Suppose that denotes the number of derangements x such that . As the main result, we show that if and z is a permutation such that for and for , then where . |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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