Large sets avoiding affine copies of infinite sequences

A conjecture of Erd\H{o}s states that for any infinite set $A \subseteq \mathbb R$,thereexists$E \subseteq \mathbb R$ of positive Lebesgue measure that does not contain any nontrivial affine copy of $A$. The conjecture remains open for most fast-decaying sequences, including the geometric sequence $A = {2^{-k} : k \geq 1}$. In this article, we consider infinite decreasing sequences $A=\{a_k:k\ge 1\}$ in $\mathbb{R}$ that converge to zero at a prescribed rate; namely $\log (a_n\mathrm{/}{a}_{n+1})=e^{\phi (n)}$, where $\phi (n)\mathrm{/}n\to 0$ as $n\to \mathrm{\infty }$. This condition is satisfied by sequences whose logarithm has polynomial decay, and in particular by the geometric sequence. For any such sequence $A$, we construct a Borel set ${\mathcal O}\subseteq \mathbb R$ of Hausdorff dimension 1, but Lebesgue measure zero, that avoids all nontrivial affine copies of $A\cup \{0\}$.