Precovering status of Gorenstein projective modules over arbitrary rings (ZFC)
Determine whether for every ring R the class 𝔾ℙ_R of Gorenstein projective left R-modules is a precovering class in ZFC (equivalently, whether every R-module admits a 𝔾ℙ_R-precover).
References
For $\mathcal{GP}$, the answer is affirmative in ZFC for certain kinds of rings, and for all rings if there are large cardinals (, ), but it is still open in general.
                — Approximation Theory and Elementary Submodels
                
                (2405.19634 - Cox, 30 May 2024) in Section 5.4 (Gorenstein Homological Algebra), Subsubsection “ZFC results”