Computing stationary probability distributions and large deviation rates for constrained random walks. The undecidability results

Our model is a constrained homogeneous random walk in .The convergence to stationarity for such a random walk can often be checked by constructing a Lyapunov function.The same Lyapunov function can also be used for computing approximately the stationary distribution of this random walk,using methods developed by Meyn and Tweedie in [34 ].In this paper we show that,for stationary homogeneous random walks,computing the stationary probability exactly is an undecidable problem,even if a Lyapunov function is available.That is no algorithm can exist to achieve this task.We then prove that computing large deviation rates for this model is also an undecidable problem.We extend these results to a certain type of queueing systems.The implication of these results is that no useful formulas for computing stationary probabilities and large deviations rates can exist in these systems.

By: David P. Gamarnik

Published in: RC22607 in 2002

LIMITED DISTRIBUTION NOTICE:

This Research Report is available. This report has been submitted for publication outside of IBM and will probably be copyrighted if accepted for publication. It has been issued as a Research Report for early dissemination of its contents. In view of the transfer of copyright to the outside publisher, its distribution outside of IBM prior to publication should be limited to peer communications and specific requests. After outside publication, requests should be filled only by reprints or legally obtained copies of the article (e.g., payment of royalties). I have read and understand this notice and am a member of the scientific community outside or inside of IBM seeking a single copy only.

RC22607.pdf

Questions about this service can be mailed to reports@us.ibm.com .