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Near-Optimal Separators in String Graphs

Published online by Cambridge University Press:  07 October 2013

JIŘÍ MATOUŠEK*
Affiliation:
Department of Applied Mathematics and Institute of Theoretical Computer Science (ITI), Charles University, Malostranské nám. 25, 11800 Praha 1, Czech Republic and Institute of Theoretical Computer Science, ETH Zurich, 8092 Zurich, Switzerland (e-mail: [email protected])

Abstract

Let G be a string graph (an intersection graph of continuous arcs in the plane) with m edges. Fox and Pach proved that G has a separator consisting of $O(m^{3/4}\sqrt{\log m})$ vertices, and they conjectured that the bound of $O(\sqrt m)$ actually holds. We obtain separators with $O(\sqrt m \,\log m)$ vertices.

Type
Paper
Copyright
Copyright © Cambridge University Press 2013 

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References

[1]Biswal, P., Lee, J. R. and Rao, S. (2010) Eigenvalue bounds, spectral partitioning, and metrical deformations via flows. J. Assoc. Comput. Mach. 57 #13.Google Scholar
[2]Feige, U., Hajiaghayi, M. T. and Lee, J. R. (2008) Improved approximation algorithms for minimum weight vertex separators. SIAM J. Comput. 38 629657.CrossRefGoogle Scholar
[3]Fox, J. and Pach, J. (2008) Separator theorems and Turán-type results for planar intersection graphs. Adv. Math. 219 10701080.CrossRefGoogle Scholar
[4]Fox, J. and Pach, J. (2010) A separator theorem for string graphs and its applications. Combin. Probab. Comput. 19 371390.CrossRefGoogle Scholar
[5]Fox, J. and Pach, J. (2014) Applications of a new separator theorem for string graphs. Combin. Probab. Comput. 23 6674.CrossRefGoogle Scholar
[6]Kolman, P. and Matoušek, J., J. (2004) Crossing number, pair-crossing number, and expansion. J. Combin. Theory Ser. B 92 99113.Google Scholar
[7]Leighton, T. and Rao, S. (1999) Multicommodity max-flow min-cut theorems and their use in designing approximation algorithms. J. Assoc. Comput. Mach. 46 787832.CrossRefGoogle Scholar
[8]Pach, J. and Tóth, G. (2000) Which crossing number is it anyway? J. Combin. Theory Ser. B 80 225246.CrossRefGoogle Scholar
[9]Rabinovich, Y. (2008) On average distortion of embedding metrics into the line. Discrete Comput. Geom. 39 720733.Google Scholar
[10]Tóth, G. (2012) A better bound for pair-crossing number. In Thirty Essays on Geometric Graph Theory (Pach, J., ed.), Springer, pp. 563567.Google Scholar