- Volume 53 Issue 1
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NOTES ON A QUESTION RAISED BY E. CALABI
- Euh, Yunhee (Division of Mathematical Models National Institute for Mathematical Sciences) ;
- Sekigawa, Kouei (Department of Mathematics Faculty of Science Niigata University)
- Received : 2014.12.15
- Published : 2016.01.31
We show that any orthogonal almost complex structure on a warped product Riemannian manifold of an oriented closed surface with nonnegative Gaussian curvature and a round 4-sphere is never integrable. This provides a partial answer to a question raised by E. Calabi.
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