Random walks with "back buttons" (extended abstract)

Ronald Fagin, Anna R. Karlin, Jon Kleinberg, Prabhakar Raghavan, Sridhar Rajagopalan, Ronitt Rubinfeld, Madhu Sudan, Andrew Tomkins

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review


We introduce backoff processes, an idealized stochastic model of browsing on the world-wide web, which incorporates both hyperlink traversals and use of the "back button" With some probability the next state is generated by a distribution over out-edges from the current state, as in a traditional Markov chain. With the remaining probability, however, the next state is generated by clicking on the back button, and returning to the state from which the current state was entered by a "forward move". Repeated clicks on the back button require access to increasingly distant history. We show that this process has fascinating similarities to and differences from Markov chains. In particular, we prove that like Markov chains, backoff processes always have a limit distribution, and we give algorithms to compute this distribution. Unlike Markov chains, the limit distribution may depend on the start state.

Original languageEnglish
Title of host publicationProceedings of the 32nd Annual ACM Symposium on Theory of Computing, STOC 2000
Number of pages10
StatePublished - 2000
Externally publishedYes
Event32nd Annual ACM Symposium on Theory of Computing, STOC 2000 - Portland, OR, United States
Duration: 21 May 200023 May 2000

Publication series

NameProceedings of the Annual ACM Symposium on Theory of Computing
ISSN (Print)0737-8017


Conference32nd Annual ACM Symposium on Theory of Computing, STOC 2000
Country/TerritoryUnited States
CityPortland, OR


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