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Foata ​

Foata's fundamental bijection: cycles rotated to their max, ordered by increasing max, parentheses erased.

Foata(Permutation)Foata's fundamental bijection: cycles rotated to their max, ordered by increasing max, parentheses erased.
Typed signatures
TypePackageApplies
(permutation) -> permutationcombinatoricsalways

Domain: Combinatorial maps

Details
  • Takes a Permutation and returns a Permutation — a typed map, so a wrong carrier is a type error rather than a wrong answer.
  • The first fundamental transformation — it sends a permutation with k cycles to one with k left-to-right maxima. (The catalog's title also names maj → inv, which is the SECOND fundamental transformation's property; this map is the first.)

Examples

Basic #

the one-line word 231231

live ↗
InFoata(Permutation⁡([2,3,1]))\mathrm{Foata}({\operatorname{Permutation}}([2, 3, 1]))OutPermutation⁡([3,1,2]){\operatorname{Permutation}}([3, 1, 2])
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Examples1
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