Published online by Cambridge University Press: 14 July 2016
Recently, Ball and Donnelly (1987) investigated the nature of the interparticle dependence in a death process with non-linear rates. In this note, after some remarks on their result, a similar problem is examined for a linear death process where the death rate per particle is a monotone function of the current state of a random environment. It is proved that if the exterior process involved is a homogeneous birth-and-death process valued in ℕ, then the survival times of any subset of particles are positively upper orthant dependent. A simple example shows that this property is not valid for general exterior processes.
This research was partially supported by a grant of the Belgium F.N.R.S.
The paper was written while the authors were visting the Statistics and Applied Probability Program, University of California, Santa Barbara.