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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

Abstract

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.

Keywords

orthogonal complex structure;warped product;curvature identity

References

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