Dice Question Streamline Icon: https://streamlinehq.com

Topological Erdős similarity conjecture for uncountable sets in non-meager Baire sets

Prove that for every uncountable subset F of the real line, there exists a non-meager Baire subset A of the real line that contains no affine image of F, thereby showing that uncountable sets are not universal in the class of non-meager Baire sets.

Information Square Streamline Icon: https://streamlinehq.com

Background

The paper studies point configurations inside sets with sufficient topological structure and proves that bounded countable sets are universal in non-meager Baire sets, both in Euclidean spaces and more general topological vector spaces. This contrasts with the classical measure-theoretic setting and motivates a topological analogue of the Erdős similarity conjecture.

The conjecture concerns whether uncountable sets can always be avoided by some non-meager Baire set under affine transformations, i.e., that uncountable sets are not universal in the class of non-meager Baire sets. The authors note partial results: for countable sets universality holds in co-meager sets and, via their main theorem, in non-meager Baire sets; for uncountable sets, Gallagher–Lai–Weber have shown certain Cantor sets are not universal, but the general statement for all uncountable sets remains unresolved.

References

This article fits into the broader context of investigating a topological variant of the Erd\H{o}s similarity conjecture: For each uncountable set $F$, there exists a non-meager Baire set $A$ that contains no affine image of $F$.

Point configurations in sets of sufficient topological structure and a topological {E}rdős similarity conjecture (2502.10204 - McDonald et al., 14 Feb 2025) in Introduction (Section 1)