机构地区: 华南师范大学南海校区学院数学系
出 处: 《数学进展》 2000年第4期345-353,共9页
摘 要: 考虑初始测度为 Lebesgue测度μ的超α-对称稳定(记为α-SS)过程,其分枝特征为■(x,z)=-γ(x)z1+β0(<β≤-1).本文研究这类超过程的局部灭绝性.运用纯分析的方法我们首先得到了局部灭绝的一个充分条件,借助这一条件,对较特殊的γ(x)=(1+|x|)θ(θ<βd);证明了与之联系的超α-SS过程存在局部灭绝的临界值 θ*,同时给出它的一个上界 βd-a若 γ(x)■ 1;这意味着 d≤-α,类似的结果可见于山.最后,我们针对γ(x)无界的情形做了一些讨论. in this paper, we deal with the local extinction of super a-symmetric stable processes (denoted by super a-SS) with the branching characteristic ■(x, z) = -r(x)z1+β(0 < β <- 1) in Mp(Rd), and present a sufficient condition for its local extinction. Our result relies on the dimension of underly space and the chacteristic of the super or-SS processes. This result is also available to 700 which may be unbounded. For the case (x) 1, this equivalent to the condition that βd <- α) the similar result is established by Dawson in 1977. In particular, if r(x) = (1 + |x|)' with θ < βd, then we prove that there is a critical value θ*, which has an upper bound βd - a, and the related super α-SS processes is locally extinct if and only if θ 3 θ*.