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KnuthClassRepresentative ​

The row reading word of σ's RSK insertion tableau — the canonical word of its Knuth (plactic) class.

KnuthClassRepresentative(Permutation)The row reading word of σ's RSK insertion tableau — the canonical word of its Knuth (plactic) class.
Typed signatures
TypePackageApplies
(permutation) -> permutationcombinatoricsalways

Domain: Combinatorial maps

Details
  • Takes a Permutation and returns a Permutation — a typed map, so a wrong carrier is a type error rather than a wrong answer.
  • Two permutations are Knuth-equivalent exactly when they share an insertion tableau (Schensted), so reading that tableau back out — bottom row to top, left to right — picks one fixed representative per class. Idempotent: the representative's own insertion tableau is the same P, so applying this again changes nothing.

Examples

Basic #

the one-line word 231231

live ↗
InKnuthClassRepresentative(Permutation⁡([2,3,1]))\mathrm{KnuthClassRepresentative}({\operatorname{Permutation}}([2, 3, 1]))OutPermutation⁡([2,1,3]){\operatorname{Permutation}}([2, 1, 3])
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Examples1