Let E\subset\R^d be compact, d\ge2, and \dim_HE>S=d/2. Either Lemma 5.5 already proves that its distance set has positive Lebesgue measure, or the following construction is possible.
After a similarity there are compact separated sets E_1,E_2\subset E and probabilities \mu_i supported on them, each satisfying
\mu_i(B(x,u))\le C u^{S+\chi}
for a fixed \chi>0. Their cross directions lie in a fixed arbitrarily small spherical patch. For every sufficiently small fixed \omega>0, there are decreasing Borel pair sets \Gamma_N\subset E_1\times E_2 such that
- 1.
(\mu_1\otimes\mu_2)(\bigcap_N\Gamma_N)>0;
- 2.
\Gamma_N is a disjoint union of at most C2^{2d\omega N} products of spatial Borel sets;
- 3.
for every e>0, there are c(e)>0, C_e<\infty and Borel B_N\subset\Gamma_N with (\mu_1\otimes\mu_2)(B_N)\le C_e2^{-c(e)N}, such that for G_N=\Gamma_N\setminus B_N, all 2^{-N}\le u\le1, and all spherical caps B(w,u),
\begin{aligned}\mu_2\{y:(x,y)\in G_N,\ \pi_x(y)\in B(w,u)\}
&\le2^{eN}u^S,\\
\mu_1\{x:(x,y)\in G_N,\ \pi_y(x)\in B(w,u)\}
&\le2^{eN}u^S.\end{aligned}
The last bounds integrate the original opposite marginal, without normalizing its individual fibers. The B_N need not have a product partition or be nested. All constants are independent of N, but may depend on the fixed measures, \omega, and e.