Curvature, Connected Sums, and Seiberg-Witten Theory
arXiv:math/0111228
Abstract
We consider several differential-topological invariants of compact 4-manifolds which directly arise from Riemannian variational problems. Using recent results of Bauer and Furuta, we compute these invariants in many cases that were previously intractable. In particular, we are now able to calculate the Yamabe invariant for certain connected sums of complex surfaces.
29 pages, LaTeX2e. Final version, to appear in Communications in Analysis and Geometry. Additions include expanded discussion of foundational material concerning the Bauer-Furuta invariant and monopole classes