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Precovering status of Gorenstein Projective modules over every ring

Determine whether, for every unital associative ring R, the class of Gorenstein Projective left R-modules is a precovering class; equivalently, ascertain whether for every R-module K there exists a morphism π_K: G_K → K with G_K Gorenstein Projective such that every morphism from a Gorenstein Projective module into K factors through π_K.

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Background

Precovering (weakly coreflective) classes are central in relative homological algebra; establishing that a class is precovering enables the existence of approximation morphisms from that class into arbitrary modules, facilitating the development of homological constructions.

Deconstructibility is a powerful sufficient condition for a class to be precovering, and the paper shows Maximum Deconstructibility is equivalent to Vopěnka’s Principle. Despite progress via large cardinal assumptions and relative consistency results, the fundamental question of whether the class of Gorenstein Projective modules itself is universally precovering remains unresolved.

References

For example, whether the class of Gorenstein Projective modules is a precovering class (over every ring) is a well-known open problem (, , , , , , , , , , , , , , ), though some relative consistency results in set theory are known (, ).

Vopěnka's Principle, Maximum Deconstructibility, and singly-generated torsion classes (2412.19380 - Cox, 26 Dec 2024) in Section 1 (Introduction)