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NoncrossingPermutation from DyckPath ​

The noncrossing permutation Stump's bijection gives the path: the cycles of its touch points, peeled off round by round.

DyckPath → Permutation

FindStat's Mp00023, Sage's to_noncrossing_permutation. Injective: its image is the noncrossing permutations. It sends the area to the number of inversions.

Called as CombinatorialMap(x, "NoncrossingPermutation"). The head's page has its examples.

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Each element of DyckPath 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 DyckPath at each size is computed, and compared with the 171 statistics on DyckPath: those that share it are the ones the map sends it to, as far as the sizes computed show.

FindStat Mp00023

to non-crossing permutation

Matched by value: our map agrees with FindStat's image on each of the 196 rows of size at most 6 we can read (0 unread; its table has 1200 rows).

InjectionGraded mapas FindStat records them, checked by FindStat's contributors.

Sends a Dyck path DD with valley at positions {(i1,j1),…,(ik,jk)}\{(i_1,j_1),\ldots,(i_k,j_k)\} to the unique non-crossing permutation π\pi having descents {i1,…,ik}\{i_1,\ldots,i_k\} and whose inverse has descents {j1,…,jk}\{j_1,\ldots,j_k\}.
ObjectImage
[1,0][1]
[1,0,1,0][1,2]
[1,1,0,0][2,1]
[1,0,1,0,1,0][1,2,3]

Data from FindStat, the combinatorial statistic finder; the page at findstat.org/Mp00023 has the rest.