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arXiv 2202.00256math.PR
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临界点非存活的概率证明:冈顿-沃森过程及其他

Probabilistic proof for non-survival at criticality : the Galton-Watson process and more

Olivier Garet

AI总结:

本文通过概率方法证明了临界点下种群非存活的定理,并探讨了冈顿-沃森过程及混合繁殖模型的生存问题。

摘要:

在一篇著名的论文中,Bezuidenhout和Grimmett证明了接触过程在临界点会死亡。他们的证明技术常被用于研究种群模式的增长。本文旨在介绍他们的思想,以最小的技术性例子进行说明。特别是,我们恢复了关于冈顿-沃森链的基本定理:除了退化情况外,只有当生育率超过1时,才可能存活。课堂上教授的经典证明本质上是分析性的,基于生成函数和凸性论证。跟随Bezuidenhout-Grimmett的方法,我们提出了一种更符合概率直觉的证明。我们还研究了混合有性与无性繁殖的生存问题。

英文摘要:

In a famous paper, Bezuidenhout and Grimmett demonstrated that the contact process dies out at the critical point.Their proof technique has often been used to study the growth of population patterns. The present text is intended as an introduction to their ideas, with examples of minimal technicality. In particular, we recover the basic theorem about Galton-Watson chains: except in a degenerate case, survival is possible only if the fertility rate exceeds 1. The classical proof that is taught in classrooms is essentially analytic, based on generating functions and convexity arguments. Following the Bezuidenhout-Grimmett way, we propose a proof that is more consistent with probabilistic intuition. We also study the survival problem for a cooperative model, mixing sexual and asexual reproduction.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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