English

Cardinal Invariants Associated with Hausdorff Capacities

Logic 2009-09-25 v1

Abstract

This is a revision (and partial retraction) of my previous abstarct. Let λ(X)\lambda(X) denote Lebesgue measure. If X[0,1]X\subseteq [0,1] and r(0,1)r \in (0,1) then the rr-Hausdorff capacity of XX is denoted by Hr(X)H^r(X) and is defined to be the infimum of all i=0λ(Ii)r\sum_{i=0}^\infty \lambda(I_i)^r where {Ii}iω\{I_i\}_{i\in\omega} is a cover of XX by intervals. The rr Hausdorff capacity has the same null sets as the rr-Hausdorff measure which is familiar from the theory of fractal dimension. It is shown that, given r<1r < 1, it is possible to enlarge a model of set theory, VV, by a generic extension V[G]V[G] so that the reals of VV have Lebesgue measure zero but still have positive rr-Hausdorff capacity.

Keywords

Cite

@article{arxiv.math/9405201,
  title  = {Cardinal Invariants Associated with Hausdorff Capacities},
  author = {Juris Steprāns},
  journal= {arXiv preprint arXiv:math/9405201},
  year   = {2009}
}