The Tóth-Varolin conjecture asserts that a Stein manifold diffeomorphic to and possessing the holomorphic
density property is biholomorphic to
. A biholomorphic
map, rather than an algebraic isomorphism, is
required.
Gorai (2026) reported a counterexample given by the smooth affine fourfold
The asserted properties are that is diffeomorphic to
, has the holomorphic
density property, and is not biholomorphic
to
. The last assertion is stronger than failure of algebraic
isomorphism. The paper is labeled preliminary.