Geography of symplectic 4–manifolds with Kodaira dimension one

Abstract

The geography problem is usually stated for simply connected symplectic 4–manifolds. When the first cohomology is nontrivial, however, one can restate the problem taking into account how close the symplectic manifold is to satisfying the conclusion of the Hard Lefschetz Theorem, which is measured by a nonnegative integer called the degeneracy. In this paper we include the degeneracy as an extra parameter in the geography problem and show how to fill out the geography of symplectic 4–manifolds with Kodaira dimension 1 for all admissible triples.