FoataMajorToInversions from Permutation
Foata's bijection: each letter is put on the end of the image so far, which is cut into blocks, and every block is rotated one place right.
FindStat's Mp00067, Sage's foata_bijection. It sends the major index to the number of inversions; the inverse is FoataInversionsToMajor. Not the cycle-based Foata, which is FindStat's first fundamental transformation.
Called as CombinatorialMap(x, "FoataMajorToInversions"). The head's page has its examples.
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Explore
Each element of Permutation at a size, and its image, applied in your browser; sizes past 7 are not offered.
Properties
Transport a statistic
Pick a statistic on Permutation. Its distribution over the images of Permutation at each size is computed, and compared with the 323 statistics on Permutation: those that share it are the ones the map sends it to, as far as the sizes computed show.
Also from
The same name out of other carriers, each its own implementation: IntegerComposition, BinaryWord.
FindStat Mp00067
Foata bijection
Matched by value: our map agrees with FindStat's image on each of the 873 rows of size at most 6 we can read (0 unread; its table has 1200 rows).
BijectionGraded mapas FindStat records them, checked by FindStat's contributors.
| Object | Image |
|---|---|
[1] | [1] |
[1,2] | [1,2] |
[2,1] | [2,1] |
[1,2,3] | [1,2,3] |
Data from FindStat, the combinatorial statistic finder; the page at findstat.org/Mp00067 has the rest.