MA or PFA as substitutes for CH in the non-plasticity conclusion for small dense subsets of ℝ
Ascertain whether Martin’s Axiom (MA) or the Proper Forcing Axiom (PFA) suffices to imply that every dense subset X of the real line with cardinality |X| < 𝔠 is not plastic, thereby replacing the CH assumption in Corollary 4.
References
We also do not know whether CH in Corollary~\ref{c:CH} can be replaced by other Set-Theoretic Axiom like MA (the Martin's Axiom ) or PFA (the Proper Forcing Axiom ).
                — Plastic metric spaces and groups
                
                (2510.10537 - Banakh et al., 12 Oct 2025) in Section: Final remarks and open problems