Gluing 4-manifolds along Σ(2,3,11)

A product formula for Seiberg–Witten invariants is proved in the case when the 4-manifold under examination is split along the Seifert fibered homology sphere Σ(2,3,11). As an application of the formula homotopy K3 surfaces not containing any of the nuclei N(2)p,q are constructed. As another application we study embeddings of Σ(2,3,11) into homotopy K3 surfaces.