The folklore conjecture on Gorenstein rings of countable Cohen–Macaulay representation type

A Gorenstein ring is a commutative Noetherian local ring whose canonical module is isomorphic to the ring itself, and its Cohen–Macaulay representation type describes the cardinality of the isomorphism classes of indecomposable maximal Cohen–Macaulay modules. Folklore conjecture. A Gorenstein ring of countable Cohen–Macaulay representation type is a hypersurface. This extends the known characterization that Gorenstein rings of finite Cohen–Macaulay representation type are hypersurfaces; the countable case is presented as a natural conjecture and remains unresolved in the supplied source.