## Abstract

A model for cleaning a graph with brushes was recently introduced. We consider the minimum number of brushes needed to clean d-regular graphs in this model, focusing on the asymptotic number for random d-regular graphs. We use a degree-greedy algorithm to clean a random d-regular graph on n vertices (with dn even) and analyze it using the differential equations method to find the (asymptotic) number of brushes needed to clean a random d-regular graph using this algorithm (for fixed d). We further show that for any d-regular graph on n vertices at most n(d + 1)/4 brushes suffice and prove that, for fixed large d, the minimum number of brushes needed to clean a random d-regular graph on n vertices is asymptotically almost surely n/4(d+o(d)), thus solving a problem raised in [M.E. Messinger, R.J. Nowakowski, P. Prałat, and N. Wormald, Cleaning random d-regular graphs with brushes using a degree-greedy algorithm, in Combinatorial and Algorithmic Aspects of Networking, Lecture Notes in Comput. Sci. 4852, Springer, Berlin-Heidelberg, 2007, pp. 13-26].

Original language | English (US) |
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Pages (from-to) | 233-250 |

Number of pages | 18 |

Journal | SIAM Journal on Discrete Mathematics |

Volume | 23 |

Issue number | 1 |

DOIs | |

State | Published - Dec 1 2008 |

Externally published | Yes |

## All Science Journal Classification (ASJC) codes

- Mathematics(all)

## Keywords

- Cleaning process
- Degree-greedy algorithm
- Differential equations method
- Random d-regular graphs