FoataInversionsToMajor from Permutation
The inverse of Foata's major-to-inversions bijection: peel off the last letter, rotate the blocks of the rest back.
FindStat's Mp00175, Sage's foata_bijection_inverse. It sends the number of inversions to the major index.
Called as CombinatorialMap(x, "FoataInversionsToMajor"). The head's page has its examples.
Live
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 Mp00175
inverse 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/Mp00175 has the rest.