Fragmentation Processes Derived from Conditioned Stable Galton-Watson Trees

Authors Gabriel Berzunza Ojeda , Cecilia Holmgren

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Gabriel Berzunza Ojeda
  • Department of Mathematical Sciences, University of Liverpool, United Kingdom
Cecilia Holmgren
  • Department of Mathematics, Uppsala University, Sweden

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Gabriel Berzunza Ojeda and Cecilia Holmgren. Fragmentation Processes Derived from Conditioned Stable Galton-Watson Trees. In 33rd International Conference on Probabilistic, Combinatorial and Asymptotic Methods for the Analysis of Algorithms (AofA 2022). Leibniz International Proceedings in Informatics (LIPIcs), Volume 225, pp. 3:1-3:14, Schloss Dagstuhl – Leibniz-Zentrum für Informatik (2022)


We study the fragmentation process obtained by deleting randomly chosen edges from a critical Galton-Watson tree 𝐭_n conditioned on having n vertices, whose offspring distribution belongs to the domain of attraction of a stable law of index α ∈ (1,2]. This fragmentation process is analogous to that introduced in the works of Aldous, Evans and Pitman (1998), who considered the case of Cayley trees. Our main result establishes that, after rescaling, the fragmentation process of 𝐭_n converges as n → ∞ to the fragmentation process obtained by cutting-down proportional to the length on the skeleton of an α-stable Lévy tree of index α ∈ (1,2]. We further establish that the latter can be constructed by considering the partitions of the unit interval induced by the normalized α-stable Lévy excursion with a deterministic drift studied by Miermont (2001). In particular, this extends the result of Bertoin (2000) on the fragmentation process of the Brownian CRT.

Subject Classification

ACM Subject Classification
  • Mathematics of computing → Probabilistic algorithms
  • Additive coalescent
  • fragmentation
  • Galton-Watson trees
  • spectrally positive stable Lévy processes
  • stable Lévy tree
  • Prim’s algorithm


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