Associativity properties of the symplectic sum

Dusa McDuff, Margaret Symington
1996 Mathematical Research Letters  
In this note we apply a 4-fold sum operation to develop an associativity rule for the pairwise symplectic sum. This allows us to show that certain diffeomorphic symplectic 4-manifolds made out of elliptic surfaces are in fact symplectically deformation equivalent. We also show that blow-up points can be traded from one side of a symplectic sum to another without changing the symplectic deformation class of the resulting manifold.
doi:10.4310/mrl.1996.v3.n5.a3 fatcat:6h4kjexl6rbhfc7xni2fkcpby4