English

The support of the free additive convolution of multi-cut measures

Probability 2022-03-29 v2 Mathematical Physics math.MP

Abstract

We consider the free additive convolution μαμβ\mu_\alpha\boxplus\mu_\beta of two probability measures μα\mu_\alpha and μβ\mu_\beta, supported on respectively nαn_\alpha and nβn_\beta disjoint bounded intervals on the real line, and derive a lower bound and an upper bound that is strictly smaller than 2nαnβ2n_\alpha n_\beta, on the number of connected components in its support. We also obtain the corresponding results for the free additive convolution semi-group {μt:t1}\{\mu^{\boxplus t}\,:\, t\ge 1\}. Throughout the paper, we consider classes of probability measures with power law behaviors at the endpoints of their supports with exponents ranging from 1-1 to 11. Our main theorem generalizes a result of Bao, Erd\H{o}s and Schnelli~[4] to the multi-cut setup.

Keywords

Cite

@article{arxiv.2201.05582,
  title  = {The support of the free additive convolution of multi-cut measures},
  author = {Philippe Moreillon and Kevin Schnelli},
  journal= {arXiv preprint arXiv:2201.05582},
  year   = {2022}
}

Comments

Corrected the proof and statement of Proposition 4.12 (Prop. 4.10 in v1). The upper bound in Theorem 1.5 accordingly changed to $2n_\alpha n_\beta$ from $n_\alpha n_\beta$, proof of Theorem 1.5 in Section 5 is now shorter. Extended Lemma 4.9 yielding a lower bound on the number of components in the support of the free additive convolution in Theorem 1.5. Corrected the proof of Proposition 4.10