Limit theorems for conditioned non-generic Galton-Watson trees

作者：Kortchemski Igor^*

来源：Annales de l Institut Henri Poincare-Probabilites et Statistiques, 2015, 51(2): 489-511.

DOI：10.1214/13-AIHP580

• Condensation
• Subcritical Galton-Watson trees
• Scaling limits
• Subexponential distributions

We study a particular type of subcritical Galton-Watson trees, which are called non-generic trees in the physics community. In contrast with the critical or supercritical case, it is known that condensation appears in certain large conditioned non-generic trees, meaning that with high probability there exists a unique vertex with macroscopic degree comparable to the total size of the tree. Using recent results concerning subexponential distributions, we investigate this phenomenon by studying scaling limits of such trees and show that the situation is completely different from the critical case. In particular, the height of such trees grows logarithmically in their size. We also study fluctuations around the condensation vertex.

• 出版日期2015-5