Examples of Convergence and Non-convergence of Markov Chains Conditioned Not To Die
Jon Warren (University of Warwick)
Abstract
In this paper we give two examples of evanescent Markov chains which exhibit unusual behaviour on conditioning to survive for large times. In the first example we show that the conditioned processes converge vaguely in the discrete topology to a limit with a finite lifetime, but converge weakly in the Martin topology to a non-Markovian limit. In the second example, although the family of conditioned laws are tight in the Martin topology, they possess multiple limit points so that weak convergence fails altogether.
Full Text: Download PDF | View PDF online (requires PDF plugin)
Pages: 1-22
Publication Date: October 3, 2001
DOI: 10.1214/EJP.v7-100
References
- Bertoin, J. and Doney, R. A. (1994), On conditioning a random walk to stay positive, Ann. Probab. 22, 2152-2167. Math. Review 96b:60168
- Billingsley, P. (1968), Convergence of Probability Measures, Wiley,New York. Math. Review 38:1718
- Breyer, L. A. and Roberts, G. O. (1999), A quasi-ergodic theorem for evanescent processes, Stoch. Proc. Appl. 84, 177-186. Math. Review 2001d:60079
- Breyer, L. A. and Hart, A. G. (2000), Approximations of quasi-stationary distributions for Markov chains. Stochastic models in engineering, technology, and management (Gold Coast, 1996), Math. Comput. Modelling 31 (10-12), 69-79. Math. Review 1 768 783
- Breyer, L. A. (1997), Quasistationarity and conditioned Markov processes., Ph. D. Thesis, The University of Queensland. Math. Review number not available.
- Coolen-Schrijner, P., Hart, A. and Pollett, P.K. (2000), Quasistationarity of continuous-time Markov chains with positive drift, J. Austral. Math. Soc. Ser. B 41, 423-441. Math. Review 1 753 121
- Darroch, J. N. and Seneta, E. (1967), Quasistationarity of continuous-time Markov chains with positive drift, J. Appl. Prob. 4, 192-196. Math. Review 35:3731
- Gibson, D. and Seneta, E. (1987), Monotone infinite stochastic matrices and their augmented truncations, Stoch. Proc. Appl. 24, 287-292. Math. Review 89h:60110
- Jacka, S. D. and Roberts, G. O. (1997), On strong forms of weak convergence, Stoch. Proc. Appl. 67, 41-53. Math. Review 98d:60008
- Jacka, S. D. and Roberts, G. O. (1995), Weak convergence of conditioned processes on a countable state space, J. Appl. Prob.32, 41-53. Math. Review 96k:60190
- Karlin, S. and McGregor, J. (1959), Coincident probabilities, Pacific J. Maths.9, 1141--1164. Math. Review 22:5072
- Kendall, D. G. and Reuter, G. E. H. (1956) Some pathological Markov processes with a denumerable infinity of states and the associated semigroups of operators on $l$, Proceedings of the International Congress of Mathematicians, 1954, Amsterdam, III, North-Holland, Amsterdam, 435-445. Math. Review 19:586e
- Meyer, P. A. (1968), Processus de Markov: La Fronti'ere de Martin, Lecture Notes in Mathematics 920, Springer, Berlin Heidelberg New York. Math. Review 39:7669
- Parthasarthy, K. R. (1967), Probability Measures on Metric Spaces, Academic Press. Math. Review 37:2271
- Pinsky, R. G. (1985), On the convergence of diffusion processes conditioned to remain in a bounded region for a large time to limiting positive recurrent diffusion processes, Ann. Probab. 13, 363-378. Math. Review 86i:60201
- Pollak, M. and Siegmund, D. (1986), Convergence of quasi-stationary distributions for stochastically monotone Markov processes, J. Appl. Prob.23, 215-220. Math. Review 87f:60101
- Roberts, G. O. (1991), A comparison theorem for conditioned Markov processes, J. Appl. Prob.28, 74--83. Math. Review 92e:60148
- Roberts, G. O. (1991), Asymptotic approximations for Brownian motion boundary hitting times, Ann. Probab.19, 1689--1731. Math. Review 92k:60188b
- Roberts, G. O. and Jacka, S. D. (1994), Weak convergence of conditioned birth and death processes, J. Appl. Prob.31, 90--100. Math. Review 95b:60090
- Roberts, G. O., Jacka, S. D, and Pollett, P. K. (1997), Non-explosivity of limits of conditioned birth and death processes, J. Appl. Prob.34, 34--45. Math. Review 98a:60124
- Rudin, W. (1991), Functional Analysis, 2nd Edn., McGraw-Hill, New York. Math. Review 92k:46001
- Seneta, E. (1981), Non-negative Matrices and Markov Chains, Springer, Berlin Heidelberg New York. Math. Review 85i:60058
- Seneta, E. and Vere-Jones, D. (1966), On quasi-stationary distributions in discrete-time Markov chains with a denumerable infinity of states, J. Appl. Prob.3, 403--434. Math. Review 34:6863
- Williams, D. (1979), Diffusions, Markov Processes and Martingales, Vol I, Wiley, New York. Math. Review 80i:60100

This work is licensed under a Creative Commons Attribution 3.0 License.