English

Sums of Commutators in Free Probability

Operator Algebras 2024-05-31 v2 Combinatorics

Abstract

We study the linear span of commutators of free random variables and show that these are the only quadratic forms which satisfy the following equivalent properties: * preservation free infinite divisibility * free and strong cancellation of odd cumulants * symmetric distribution for any free family. The main combinatorial tool is an involution on non-crossing partitions.

Keywords

Cite

@article{arxiv.2002.06051,
  title  = {Sums of Commutators in Free Probability},
  author = {Wiktor Ejsmont and Franz Lehner},
  journal= {arXiv preprint arXiv:2002.06051},
  year   = {2024}
}

Comments

21 pages; numerous improvements suggested by an anonymous referee; figures changed to black and white (color can be switched on in latex file); limit theorems moved to separate paper arXiv:2004.02679

R2 v1 2026-06-23T13:41:59.810Z