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KasraouiZeng ​

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

KasraouiZeng(SetPartition)The Kasraoui-Zeng involution: exchanges the number of crossings with the number of nestings.
Typed signatures
TypePackageApplies
(set_partition) -> set_partitioncombinatoricsalways

Domain: Combinatorial maps

Details
  • Takes a SetPartition and returns a SetPartition — a typed map, so a wrong carrier is a type error rather than a wrong answer.
  • FindStat's Mp00115, defined in Kasraoui and Zeng's "Distribution of crossings, nestings and alignments of two edges in matchings and partitions".

Examples

Basic #

the nesting {1,4}∣{2,3}\{1,4\} \mid \{2,3\}

live ↗
InKasraouiZeng(SetPartition⁡([[1,4],[2,3]]))\mathrm{KasraouiZeng}({\operatorname{SetPartition}}([[1, 4], [2, 3]]))OutSetPartition⁡([[1,3],[2,4]]){\operatorname{SetPartition}}([[1, 3], [2, 4]])
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Examples1
CrosswalkFindStat