Box dimension of generic Hölder level sets

Zoltán Buczolich, Balázs Maga

Published 2023-06-07Version 1

Hausdorff dimension of level sets of generic continuous functions defined on fractals can give information about the "thickness/narrow cross-sections" "network" corresponding to a fractal set, $F$. This lead to the definition of the topological Hausdorff dimension of fractals. Finer information might be obtained by considering the Hausdorff dimension of level sets of generic $1$-H\"older-$\alpha$ functions, which has a stronger dependence on the geometry of the fractal, as displayed in our previous papers. In this paper, we extend our investigations to the lower and upper box-counting dimension as well: while the former yields results highly resembling the ones about Hausdorff dimension of level sets, the latter exhibits a different behaviour. Instead of "finding narrow-cross sections", results related to upper box-counting dimension try to "measure" how much level sets can spread out on the fractal, how widely the generic function can "oscillate" on it. Key differences are illustrated by giving estimates concerning the Sierpi\'nski triangle.