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Classes of sets with large intersection

Published online by Cambridge University Press:  26 February 2010

K. J. Falconer
Affiliation:
School of Mathematics, University Walk, Bristol, BS8 1TW
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If E1 and E2 are subsets of ℝn and a- is an isometry or similarity transformation, it is useful to be able to estimate the Hausdorff dimension of E1 ∩ σ(E2) in terms of the dimensions of E1 and E2. If E1 and E2 are compact, then, as σvaries, dim (El ∩ σ(E2)) is “in general” at most max (dim E1 + dim E2 − n, 0) and “often” at least this value (see Mattila [9] and Kahane [7] for more precise statements of these ideas). However, as we shall see, it is possible to construct non-compact sets E of any given dimension that are “sufficiently dense” in ℝn to ensure that dim (E ∩ σ(E)) = dim E for all similarities σ More generally, we shall show that for each s there are large classes of sets & of dimensions between s and n, closed under reasonable transformations including similarities, such that the intersection of any countable collection of sets in & has dimension at least s. Such collections of sets are required, for example, in the constructions of subsets of ℝn with certain dimensional properties given by Davies [1] and Falconer [5].

Type
Research Article
Copyright
Copyright © University College London 1985

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References

1.Davies, Roy O.. Fields of dimension d. To appear.Google Scholar
2.Davies, Roy O. and Fast, H.. Legesgue density influences Hausdorff measure: large sets surface-like from many directions. Mathematika, 25 (1978), 116119.CrossRefGoogle Scholar
3.Dieudonné, J.. Foundations of Modern Analysis (Academic Press, London and New York, 1960).Google Scholar
4.Falconer, K. J.. The Geometry of Fractal Sets (Cambridge University Press, 1984).Google Scholar
5.Falconer, K. J.. On the Hausdorff dimension of distance sets. Mathematika, 32 (1985), 206212.CrossRefGoogle Scholar
6.Federer, H.. Geometric Measure Theory (Springer, Berlin, 1969).Google Scholar
7.Kahane, J.-P.. Sur la dimension des intersections. To appear.Google Scholar
8.Marstrand, J. M.. The dimension of Cartesian product sets. Proc. Camb. Phil. Soc., 50 (1954), 198202.CrossRefGoogle Scholar
9.Mattila, P.. Hausdorff dimension and capacities of intersections of sets in n-space. Acta Math., 152 (1984), 77105.CrossRefGoogle Scholar
10.Rogers, C. A.. Hausdorff measures. (Cambridge University Press, 1970.Google Scholar
11.Sion, M. and Sjerve, D.. Approximation properties of measures generated by continuous set functions. Mathematika, 9 (1962), 145156.CrossRefGoogle Scholar
12.Davies, Roy O., Marstrand, J. M. and Taylor, S. J.. On the intersection of transforms of linear sets. Colloa. Math., 7 (1960), 237243.CrossRefGoogle Scholar