东北大学学报(自然科学版) ›› 2020, Vol. 41 ›› Issue (10): 1517-1520.DOI: 10.12068/j.issn.1005-3026.2020.10.022

• 数学 • 上一篇    

Galton-Watson过程中极限鞅密度函数的Lipschitz连续性

侯婉婷1, 张美娟2   

  1. (1. 东北大学 理学院, 辽宁 沈阳110819; 2. 中央财经大学 统计与数学学院, 北京100081)
  • 收稿日期:2019-10-15 修回日期:2019-10-15 出版日期:2020-10-15 发布日期:2020-10-20
  • 通讯作者: 侯婉婷
  • 作者简介:侯婉婷(1989-),女,辽宁朝阳人,东北大学讲师,博士.
  • 基金资助:
    中央高校基本科研业务费专项资金资助项目(N180503019); 国家自然科学基金资助项目(11801596); 教育部人文社会科学研究规划基金资助项目(19YJA790004).

Lipschitz Continuity of Martingale’s Limit Density Function in Galton-Watson Processes

HOU Wan-ting1, ZHANG Mei-juan2   

  1. 1.School of Sciences, Northeastern University, Shenyang 110819, China; 2.School of Statistics and Mathematics, Central University of Finance and Economics, Beijing 100081, China.
  • Received:2019-10-15 Revised:2019-10-15 Online:2020-10-15 Published:2020-10-20
  • Contact: ZHANG Mei-juan
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摘要: 考虑上临界Galton-Watson过程中第n代粒子总数Zn,令W表示鞅Wn=Zn/mn的极限.针对W的密度函数ω(x)的Lipschitz连续性问题,基于Kesten-Stigum定理,提出了更完善的证明方法和补充.同时进行了关于鞅极限性质的一系列讨论.首先修正了以往的证明方法,得到在δ≠1的情形下,ω(x)在[ε,)中是Lipschitz 连续的,阶为δ′=min(δ,1).在δ=1的时,ω(x)的Lipschitz连续性的阶为1/2,从而保证了结论的完整性.

关键词: 分枝过程, 上临界, 鞅收敛, Kesten-Stigum定理, Lipschitz连续

Abstract: Considering the total number Zn of the n-th generation particles in the supercritical Galton-Watson process, let W denote the limit of martingale Wn=Zn/mn. Aiming at the Lipschitz continuity problem of the density function ω(x) of W, based on the Kesten-Stigum theorem, a more complete proof and supplement were proposed. A series of discussions on the limit properties of martingales were also conducted. First, the previous method of proof was modified, and it was obtained that in the case of δ≠1,ω(x) is Lipschitz continuous in [ε,), and the order is δ′=min(δ,1).When δ=1, the order of Lipschitz continuity of ω(x) is 1/2, thus ensuring the completeness of the conclusion.

Key words: branching process, supercritical, martingale convergence, Kesten-Stigum theorem, Lipschitz continuous

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