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On discrepancy bounds via dual shatter function

Published online by Cambridge University Press:  26 February 2010

Jiří Matousěk
Affiliation:
Department of Applied Mathematics, Charles University, Malostranské nám. 25, 118 00 Praha 1, Czech Republic
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Abstract

Recently, it has been shown that tight or almost tight upper bounds for the discrepancy of many geometrically denned set systems can be derived from simple combinatorial parameters of these set systems. Namely, if the primal shatter function of a set system ℛ on an n-point set X is bounded by const. md, then the discrepancy disc (ℛ) = O(n(d−1)/2d) (which is known to be tight), and if the dual shatter function is bounded by const. md, then disc We prove that for d = 2, 3, the latter bound also cannot be improved in general. We also show that bounds on the shatter functions alone do not imply the average (L1)-discrepancy to be much smaller than the maximum discrepancy: this contrasts results of Beck and Chen for certain geometric cases. In the proof we give a construction of a certain asymptotically extremal bipartite graph, which may be of independent interest.

Type
Research Article
Copyright
Copyright © University College London 1997

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References

1.Alexander, R.. Geometric methods in the study of irregularities of distribution. Combinatorica, 10 (1990), 115136.CrossRefGoogle Scholar
2.Alon, N. and Spencer, J.. The Probabilistic Method (J. Wiley & Sons, 1993).Google Scholar
3.Beck, J.. Some upper bounds in the theory of irregularities of distribution. Acta Arith., 43 (1984), 115130.CrossRefGoogle Scholar
4.Beck, J. and Chen, W.. Irregularities of Distribution (Cambridge University Press, 1987).CrossRefGoogle Scholar
5.Beck, J. and Chen, W.. Irregularities of point distribution relative to half-planes I. Mathematika, 40 (1993), 102126.CrossRefGoogle Scholar
6.Beck, J. and Chen, W.. Irregularities of point distribution relative to convex polygons II. Mathematika, 40 (1993), 127136.CrossRefGoogle Scholar
7.Beck, J. and Sós, V.. Discrepancy theory. In Handbook of Combinatorics, (North-Holland, Amsterdam, 1995), pp. 14051446.Google Scholar
8.Bollobás, B.. Extremal Graph Theory (Academic Press, London, 1978).Google Scholar
9.Brown, W. G.. On graphs that do not contain a Thomsen graph. Canad. Math. Bull., 9 (1966), 281285.CrossRefGoogle Scholar
10.Harris, J.. Algebraic Geometry (Springer-Verlag, 1992).CrossRefGoogle Scholar
11.Kollar, J., Rónyai, L., and Szabó, T.. Norm-graphs and bipartite Turán numbers. Combinatorica, 16, (1996), 399406.CrossRefGoogle Scholar
12.Matoušek, J.. Tight upper bounds for the discrepancy of halfspaces. Discr. & Comput. Geom., 13 (1995), 593601.CrossRefGoogle Scholar
13.Matoušek, J., Welzl, E. and Wernisch, L.. Discrepancy and εapproximations for bounded VC-dimension. Combinatorica, 13 (1993), 455466.CrossRefGoogle Scholar