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An Extension of Foster's Network Theorem

Published online by Cambridge University Press:  12 September 2008

Prasad Tetali
Affiliation:
AT & T Bell Labs, Murray Hill, NJ 07974. Email: prasad@research.att.com

Abstract

Consider an electrical network on n nodes with resistors rij between nodes i and j. Let Rij denote the effective resistance between the nodes. Then Foster's Theorem [5] asserts that

where ij denotes i and j are connected by a finite rij. In [10] this theorem is proved by making use of random walks. The classical connection between electrical networks and reversible random walks implies a corresponding statement for reversible Markov chains. In this paper we prove an elementary identity for ergodic Markov chains, and show that this yields Foster's theorem when the chain is time-reversible.

We also prove a generalization of a resistive inverse identity. This identity was known for resistive networks, but we prove a more general identity for ergodic Markov chains. We show that time-reversibility, once again, yields the known identity. Among other results, this identity also yields an alternative characterization of reversibility of Markov chains (see Remarks 1 and 2 below). This characterization, when interpreted in terms of electrical currents, implies the reciprocity theorem in single-source resistive networks, thus allowing us to establish the equivalence of reversibility in Markov chains and reciprocity in electrical networks.

Type
Research Article
Copyright
Copyright © Cambridge University Press 1994

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References

[1]Chandra, A. K., Raghavan, P., Ruzzo, W. L., Smolensky, R. and Tiwari, P. (1989) The electrical resistance of a graph captures its commute and cover times. Proc. of the 21st Annual ACM Symp. on Theory of Computing 574586.Google Scholar
[2]Coppersmith, D., Doyle, P., Raghavan, P. and Snir, M. (to appear) Random Walks on Weighted Graphs, and Applications to On-line Algorithms. Jour. of the ACM.Google Scholar
[3]Coppersmith, D., Tetali, P. and Winkler, P. (1993) Collisions among random walks on a graph. SIAM J. on Discrete Math. 6 363374.CrossRefGoogle Scholar
[4]Doyle, P. G. and Snell, J. L. (1984) Random Walks and Electric Networks, The Mathematical Association of America.CrossRefGoogle Scholar
[5]Foster, R. M. (1949) The Average impedance of an electrical network. Contributions to Applied Mechanics (Reissner Anniversary Volume), Edwards Bros., Ann Arbor, Mich. 333340.Google Scholar
[6]Foster, R. M. (1961) An extension of a network theorem. IRE Trans. Circuit Theory 8 7576.CrossRefGoogle Scholar
[7]Hayt, W. H. Jr, and Kemmerly, J. E. (1978) Engineering Circuit Analysis, McGraw-Hill, 3rd ed.Google Scholar
[8]Kemeny, J. G. and Snell, J. L. (1983) Finite Markov Chains, Springer-Verlag.Google Scholar
[9]Kemeny, J. G., Snell, J. L. and Knapp, A. W. (1976) Denumerable Markov Chains, Springer-Verlag.CrossRefGoogle Scholar
[10]Tetali, P. (1991) Random Walks and the effective resistance of networks. J. Theoretical Probability 4 101109.CrossRefGoogle Scholar
[11]Tetali, P. (1994) Design of on-line algorithms using hitting times. Proceedings of the 5th annual ACM-SIAM Symp. on Discrete Algorithms, Virginia402411.Google Scholar