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Foata

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

Foata(Permutation)

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