Some central limit theorems for critical beta-splitting tree
Alexander Iksanov, Anatolii Nikitin, Roman Yakymiv
TL;DR
The paper studies critical beta-splitting trees and their connection to infinite occupancy schemes, proving joint central limit theorems for leaf-heights in both discrete and continuous versions. By coupling a balls-in-boxes scheme to a subordinator with Lévy measure $\nu$, the authors derive a unified Brownian-limit framework for $(L_{n,1},\ldots,L_{n,j},L_n,D_n)$ and establish explicit Gaussian mixtures for the coordinates $L_{n,r}$ with constants expressed through $\zeta(2)$ and $\zeta(3)$; these results hold jointly with their occupancy counterparts. The approach hinges on distributional equalities, Poissonization, and a mix of Skorokhod-space convergence and occupancy-limit theorems (notably Gnedin et al.), yielding a coherent bridge between discrete and continuous critical beta-splitting trees. The findings illuminate the asymptotic structure of tree heights and deepen the connection between random trees and infinite-occupancy models, with potential implications for related stochastic-tree models and limit theorems.
Abstract
We further explore a connection initially unveiled in Iksanov (2025) between critical beta-splitting trees and infinite `balls-in-boxes' schemes. Using the connection, we derive a new joint central limit theorem for components of the height of a leaf chosen uniformly at random in the discrete version of a critical beta-splitting tree. Also, we obtain a joint central limit theorem for the heights in the discrete and continuous versions of a critical beta-splitting tree.
