Minimality of certain normal connected sums

We show that the normal connected sum of two minimal symplectic 4-manifolds (neither of them rational or ruled) is a minimal symplectic 4-manifold. In the proof we use a symplectic sum formula for Gromov-Witten invariants.

Minimality of certain normal connected sums

We show that the normal connected sum of two minimal symplectic 4-manifolds (neither of them rational or ruled) is a minimal symplectic 4-manifold. In the proof we use a symplectic sum formula for Gromov-Witten invariants.