derangement
Sign in to savethumb|305px|Number of possible permutations and derangements of elements. ( factorial) is the number of -permutations; ( subfactorial) is the number of derangements – -permutations where all of the elements change their initial places.
Article
10 sectionsContents
- Example
- Counting derangements
- Derivation by inclusion–exclusion principle
- Growth of number of derangements as ''n'' approaches ∞
- Asymptotic expansion in terms of Bell numbers
- Generalizations
- Computational complexity
- Footnotes
- References
- External links
thumb|305px|Number of possible permutations and derangements of elements. ( factorial) is the number of -permutations; ( subfactorial) is the number of derangements – -permutations where all of the elements change their initial places.
In combinatorial mathematics, a derangement is a permutation of the elements of a set in which no element appears in its original position. In other words, a derangement is a permutation that has no fixed points.