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An exponential change of measure for the Feller diffusion and some implications for superprocesses

Published online by Cambridge University Press:  14 July 2016

Robert J. Adler*
Affiliation:
Technion, Israel Institute of Technology
Srikanth K. Iyer*
Affiliation:
Indian Institute of Technology
*
Postal address: Faculty of Industrial Engineering and Management, Technion, Haifa, 32000 Israel. Email address: [email protected]
∗∗Postal address: Department of Mathematics, Indian Institute of Technology, Kanpur, UP 27516, India. Email address: [email protected]

Abstract

Let Xt be a Feller (branching) diffusion with drift αx. We consider new processes, the probability measures of which are obtained from that of X via changes of measure involving suitably normalized exponential functions of with λ > 0. The new processes can be thought of as ‘self-reinforcing’ versions of the old.

Depending on the values of α, T and λ, the process under the new measure is shown to exhibit explosion in finite time. We also obtain a number of other results related to the new processes.

Since the Feller diffusion is also the total mass process of a superprocess, we relate the finite-time explosion property to the behaviour of superprocesses with local self-interaction, and raise some interesting questions for these.

Type
Short Communications
Copyright
Copyright © 2000 by The Applied Probability Trust 

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Footnotes

Research supported in part by US–Israel Binational Science Foundation, Israel Science Foundation, and National Science Foundation (RJA).

Research supported in part by ONR Grant No. N00014-94-1-0191 (SKI).

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