Weak Kobayashi conjecture for Calabi–Yau manifolds

Establish whether Calabi–Yau manifolds are non-Kobayashi-hyperbolic, equivalently whether every Calabi–Yau manifold contains a nonconstant entire curve, as predicted by the weak form of the Kobayashi conjecture.

Background

Kobayashi hyperbolicity means that a compact complex manifold contains no nonconstant entire curve. The paper notes that Kähler hyperbolicity implies Kobayashi hyperbolicity and proves that the fundamental group of a Calabi–Yau manifold cannot coincide with that of a Kähler hyperbolic manifold. This result is presented as partial evidence toward the unresolved weak form of the Kobayashi conjecture for Calabi–Yau manifolds.

References

Gromov observed that Kähler hyperbolicity implies Kobayashi hyperbolicity (see Cor.4.2). A weak form of the Kobayashi conjecture predicts that Calabi-Yau manifolds are not Kobayashi hyperbolic (Prob. C.1, , ); this remains widely open.

Topological obstructions to geometric positivity and negativity on Calabi-Yau manifolds  (2608.12705 - Li, 13 Aug 2026) in Section 2, Introduction to the final result; Section 2, Main results