We define a new Markov chain on proper k-colorings of graphs, and relate its convergence properties to the maximum degree β¬ of the graph. The chain is shown to have bounds on convergence time appreciably better than those for the well-known JerrumrSalasαSokal chain in most circumstances. For the cas
Fastest expected time to mixing for a Markov chain on a directed graph
β Scribed by Steve Kirkland
- Publisher
- Elsevier Science
- Year
- 2010
- Tongue
- English
- Weight
- 215 KB
- Volume
- 433
- Category
- Article
- ISSN
- 0024-3795
No coin nor oath required. For personal study only.
β¦ Synopsis
For an irreducible stochastic matrix T, the Kemeny constant K(T) measures the expected time to mixing of the Markov chain corresponding to T. Given a strongly connected directed graph D, we consider the set Ξ£ D of stochastic matrices whose directed graph is subordinate to D, and compute the minimum value of K, taken over the set Ξ£ D . The matrices attaining that minimum are also characterised, thus yielding a description of the transition matrices in Ξ£ D that minimise the expected time to mixing. We prove that K(T) is bounded from above as T ranges over the irreducible members of D if and only if D is an intercyclic directed graph, and in the case that D is intercyclic, we find the maximum value of K on the set Ξ£ D .
Throughout, our results are established using a mix of analytic and combinatorial techniques.
π SIMILAR VOLUMES
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