enumeratio

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SymmetricGroup ​

The permutations of as a lazy indexed family, in one-line form.

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SymmetricGroup(n)the permutations of .

Domain: Collections

Details
  • A lazy indexed collection: and unranks the -th permutation, so — over rows — pages as cheaply as a small one.
  • Each element is the image word ; the classical statistics (Descents, MajorIndex, Inversions, CycleCount, FixedPoints) are heads over that word.
  • The derangements — permutations with no fixed point — number . See Subfactorial.

Enumeration

See also: Factorial, Subfactorial, Count, At