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Escape from the boundary in Markov population processes

Published online by Cambridge University Press:  21 March 2016

A. D. Barbour*
Affiliation:
Universität Zürich
K. Hamza*
Affiliation:
Monash University
Haya Kaspi*
Affiliation:
Technion, Haifa
F. C. Klebaner*
Affiliation:
Monash University
*
Postal address: Institut für Mathematik, Universität Zürich, Winterthurertrasse 190, CH-8057 Zürich, Switzerland. Email address: [email protected]
∗∗ Postal address: School of Mathematical Sciences, Monash University, Clayton, VIC 3800, Australia.
∗∗∗ Postal address: Faculty of Industrial Engineering and Management, Technion, Haifa, 32000, Israel.
∗∗ Postal address: School of Mathematical Sciences, Monash University, Clayton, VIC 3800, Australia.
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Abstract

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Density dependent Markov population processes in large populations of size N were shown by Kurtz (1970), (1971) to be well approximated over finite time intervals by the solution of the differential equations that describe their average drift, and to exhibit stochastic fluctuations about this deterministic solution on the scale √N that can be approximated by a diffusion process. Here, motivated by an example from evolutionary biology, we are concerned with describing how such a process leaves an absorbing boundary. Initially, one or more of the populations is of size much smaller than N, and the length of time taken until all populations have sizes comparable to N then becomes infinite as N → ∞. Under suitable assumptions, we show that in the early stages of development, up to the time when all populations have sizes at least N1-α for 1/3 < α < 1, the process can be accurately approximated in total variation by a Markov branching process. Thereafter, it is well approximated by the deterministic solution starting from the original initial point, but with a random time delay. Analogous behaviour is also established for a Markov process approaching an equilibrium on a boundary, where one or more of the populations become extinct.

Type
General Applied Probability
Copyright
Copyright © Applied Probability Trust 2015 

References

Athreya, K. B. and Ney, P. E. (1972). Branching Processes. Springer, New York.CrossRefGoogle Scholar
Barbour, A. D. (1975). The duration of the closed stochastic epidemic. Biometrika 62, 477482.Google Scholar
Barbour, A. D. (1980). Density dependent Markov population processes. In Biological Growth and Spread (Lecture Notes Biomath. 38). Springer, Berlin, pp. 3649.Google Scholar
Barbour, A. D. and Pollett, P. K. (2012). Total variation approximation for quasi-equilibrium distributions, II. Stoch. Process Appl. 122, 37403756.CrossRefGoogle Scholar
Barbour, A. D., Hamza, K., Kaspi, H. and Klebaner, F. (2014). Escape from the boundary in Markov population processes. Preprint. Available at http://arxiv.org/abs/1312.5788v3.Google Scholar
Bartlett, M. S. (1949). Some evolutionary stochastic processes. J. R. Statist. Soc. 11, 211229.Google Scholar
Heinzmann, D. (2009). Extinction times in multitype Markov branching processes. J. Appl. Prob. 46, 296307.Google Scholar
Kendall, D. G. (1956). Deterministic and stochastic epidemics in closed populations. In Proceedings of the Third Berkeley Symposium on Mathematical Statistics and Probability, Vol. IV. University of California Press, Berkeley, pp. 149165.Google Scholar
Klebaner, F. C., Sagitov, S., Vatutin, V. A., Haccou, P. and Jagers, P. (2011). Stochasticity in the adaptive dynamics of evolution: the bare bones. J. Biol. Dyn. 5, 147162.CrossRefGoogle ScholarPubMed
Kurtz, T. G. (1970). Solutions of ordinary differential equations as limits of pure jump Markov processes. J. Appl. Prob. 7, 4958.Google Scholar
Kurtz, T. G. (1971). Limit theorems for sequences of jump Markov processes approximating ordinary differential processes. J. Appl. Prob. 8, 344356.Google Scholar
Kurtz, T. G. (1978). Strong approximation theorems for density dependent Markov chains. Stoch. Process. Appl. 6, 223240.Google Scholar
Seneta, E. (2006). Non-negative Matrices and Markov Chains. Springer, New York.Google Scholar
Thorisson, H. (2000). Coupling, Stationarity, and Regeneration. Springer, New York.Google Scholar
Whittle, P. (1955). The outcome of a stochastic epidemic—a note on Bailey's paper. Biometrika 42, 116122.Google Scholar