This article highlights a connection between Diophantine approximation and the lower Assouad dimension by using information about the latter to show that the Hausdorff dimension of the set of badly approximable points that lie in certain non-conformal fractals, known as self-affine sponges, is bounded below by the dynamical dimension of these fractals. The results, which are the first to advance beyond the conformal setting, encompass both the case of Sierpiński sponges/carpets (also known as Bedford–McMullen sponges/carpets) and the case of Barański carpets.

Article describes how the authors plant to deal with orientation preserving homeomorphisms and, more specifically, diffeomorphisms of the unit circle S1. By employing the recurrence method worked out in Pawelec the authors provide effective lower estimates of the proper-dimensional Hausdorff measure of minimal sets of circle homeomorphisms that are not conjugate to any rotation.