Shuffle-compatible permutation statistics II: The exterior peak set

Darij Grinberg

Research output: Contribution to journalArticlepeer-review


This is a continuation of the work “Shuffle-compatible permutation statistics” by Gessel and Zhuang (but can be read independently from the latter). We study the shuffle-compatibility of permutation statistics-a concept introduced by Gessel and Zhuang, although various instances of it have appeared throughout the literature before. We prove that (as Gessel and Zhuang have conjectured) the exterior peak set statistic (Epk) is shuffle-compatible. We furthermore introduce the concept of an “LR-shuffle-compatible” statistic, which is stronger than shuffle-compatibility. We prove that Epk and a few other statistics are LR-shuffle-compatible. Furthermore, we connect these concepts with the quasisymmetric functions, in particular the dendriform structure on them.

Original languageEnglish (US)
Article number#P4.17
JournalElectronic Journal of Combinatorics
Issue number4
StatePublished - Oct 19 2018

Bibliographical note

Publisher Copyright:
© The author.


  • Algebraic combinatorics
  • P-partitions
  • Permutation statistics
  • Permutations
  • Quasisymmetric functions
  • Shuffles


Dive into the research topics of 'Shuffle-compatible permutation statistics II: The exterior peak set'. Together they form a unique fingerprint.

Cite this