Minimizing Euler characteristics of symplectic four-manifolds

Abstract

We prove that the minimal Euler characteristic of a closed symplectic four-manifold with given fundamental group is often much larger than the minimal Euler characteristic of almost complex closed four-manifolds with the same fundamental group. In fact, the difference between the two is arbitrarily large for certain groups.

cosmetic changes only; final version, to appear in Proc. Amer. Math. Soc