“…Y is a smooth surface of codimension k. As in the paper [10] by Grafakos, Palsson and the first two authors, for a compact subset E ⊂ R d , we define the (two-point) Φ-configuration set of E as Our goal is to find a threshold, s 0 = s 0 (Φ), such that if dim H (E) > s 0 then ∆ Φ (E) has nonempty interior. Similar questions have been studied in, or are accessible to the methods of, a number of works, e.g., [11,2,5,23,24,21]. (There is of course an extensive literature on the related Falconer distance problem [8], and its generalizations to configurations, where the question is what lower bound on dim H (E) ensures that ∆ Φ (E) has positive Lebesque measure [41,7,6,15].)…”