Finite time extinction of super-Brownian motions with deterministic catalyst

• 作 者: 任艳霞 王永进
• 机 构: LMAM,School of Mathematics
• 出 处: 中国科学A辑
• 发表日期: 2004年期
• 关键词: super-Brownian motion compact support property finite time extinction positive s
• 基金项目: 国家自然科学基金

In this paper we consider a super-Brownian motion X with branching mechanism k(x)za, where k(x) ＞ 0 is a bounded Holder continuous function on Rd and infx∈Rd k(x) = 0. We prove that if k(x) ≥‖x‖-1(0 ≤ l ＜∞) for sufficiently large x, then X has compact support property, and for dimension d = 1, if k(x) ≥ exp(-l‖x‖)(0 ≤ l ＜∞) for sufficiently large x, then X also has compact support property. The maximal order of k(x) for finite time extinction is different between d = 1, d = 2 and d ≥3: it is O(‖x‖-(a+1))in one dimension, O(‖x‖-2(log ‖x‖)-(a+1)) in two dimensions, and O(‖x‖2) in higher dimensions. These growth orders also turn out to be the maximum order for the nonexistence of a positive solution for 1/2△u =k(x)uα.