Kodaira dimension of fiber sums along spheres

  title={Kodaira dimension of fiber sums along spheres},
  author={Josef G. Dorfmeister},
  journal={Geometriae Dedicata},
In this note we discuss the effect of the symplectic sum along spheres in symplectic four-manifolds on the Kodaira dimension of the underlying symplectic manifold. We find that the Kodaira dimension is non-decreasing. Moreover, we are able to obtain precise results on the structure of the manifold obtained from the blow down of an embedded symplectic $$-4$$-4-sphere. 

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