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KasraouiZeng from SetPartition ​

The Kasraoui-Zeng involution: exchanges the number of crossings with the number of nestings.

SetPartition → SetPartition

FindStat's Mp00115, defined in Kasraoui and Zeng's "Distribution of crossings, nestings and alignments of two edges in matchings and partitions".

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

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Each element of SetPartition at a size, and its image, applied in your browser; sizes past 7 are not offered.

Properties

Transport a statistic

Pick a statistic on SetPartition. Its distribution over the images of SetPartition at each size is computed, and compared with the 111 statistics on SetPartition: those that share it are the ones the map sends it to, as far as the sizes computed show.

FindStat Mp00115

Kasraoui-Zeng

Matched by value: our map agrees with FindStat's image on each of the 278 rows of size at most 6 we can read (0 unread; its table has 1200 rows).

BijectionGraded mapInvolutionas FindStat records them, checked by FindStat's contributors.

The Kasraoui-Zeng involution.
ObjectImage
{{1}}{{1}}
{{1,2}}{{1,2}}
{{1,2,3}}{{1,2,3}}
{{1},{2}}{{1},{2}}

Data from FindStat, the combinatorial statistic finder; the page at findstat.org/Mp00115 has the rest.