Hostname: page-component-8448b6f56d-jr42d Total loading time: 0 Render date: 2024-04-19T11:16:50.542Z Has data issue: false hasContentIssue false

Colouring Random 4-Regular Graphs

Published online by Cambridge University Press:  01 March 2007

LINGSHENG SHI
Affiliation:
Department of Combinatorics and Optimization, University of Waterloo, Waterloo ON, CanadaN2L 3G1 (e-mail: lshi@math.tsinghua.edu.cn, nwormald@uwaterloo.ca)
NICHOLAS WORMALD
Affiliation:
Department of Combinatorics and Optimization, University of Waterloo, Waterloo ON, CanadaN2L 3G1 (e-mail: lshi@math.tsinghua.edu.cn, nwormald@uwaterloo.ca)

Abstract

We show that a random 4-regular graph asymptotically almost surely (a.a.s.) has chromatic number 3. The proof uses an efficient algorithm which a.a.s. 3-colours a random 4-regular graph. The analysis includes use of the differential equation method, and exponential bounds on the tail of random variables associated with branching processes. A substantial part of the analysis applies to random d-regular graphs in general.

Type
Paper
Copyright
Copyright © Cambridge University Press 2006

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

[1]Achlioptas, D. and Moore, C. (2003) Almost all graphs with average degree 4 are 3-colourable. J. Comput. System Sci. 67 441471.CrossRefGoogle Scholar
[2]Achlioptas, D. and Naor, A. (2005) The two possible values of the chromatic number of a random graph. Ann. of Math. 162 13351351.CrossRefGoogle Scholar
[3]Bollobás, B. (1985) Random Graphs, Academic Press, New York.Google Scholar
[4]Díaz, J., Serna, M. and Wormald, N. C. Computation of the bisection width for random d-regular graphs. Theoret. Comput. Sci., to appear.Google Scholar
[5]Janson, S., Łuczak, T. and Ruciński, A. (2000) Random Graphs, Wiley, New York.CrossRefGoogle Scholar
[6]Molloy, M. and Reed, B. (1998) The size of the giant component of a random graph with a given degree sequence. Combin. Probab. Comput. 7 295305.CrossRefGoogle Scholar
[7]Shi, L. and Wormald, N. Colouring random d-regular graphs. Combin. Probab. Comput. (to appear).Google Scholar
[8]Spencer, J. and Wormald, N. Birth control for giants. Combinatorica (to appear).Google Scholar
[9]Wormald, N. C. (1981) The asymptotic distribution of short cycles in random regular graphs. J. Combin. Theory Ser. B 31 168182.CrossRefGoogle Scholar
[10]Wormald, N. C. (1995) Differential equations for random processes and random graphs. Ann. Appl. Probab. 5 12171235.CrossRefGoogle Scholar
[11]Wormald, N. C. (1999) The differential equation method for random graph processes and greedy algorithms. In Lectures on Approximation and Randomized Algorithms (Karoński, M. and Prömel, H., eds), PWN, Warsaw, pp. 73155.Google Scholar
[12]Wormald, N. C. (1999) Models of random regular graphs. In Surveys in Combinatorics (Lamb, J. D. and Preece, D. A., eds), pp. 239298.Google Scholar
[13]Wormald, N. C. (2004) Random graphs and asymptotics. Section 8.2 in Handbook of Graph Theory (Gross, J. L. and Yellen, J., eds), CRC, Boca Raton, pp. 817836.Google Scholar