Refined Seiberg-Witten invariants

This is a survey article on the stable cohomotopy refinement of Seiberg-Witten invariants containing also new results, for example:

• Stable cohomotopy groups describe path components of certain mapping spaces.
• Relation of stable cohomotopy invariants to Seiberg-Witten invariants without restriction on Betti numbers.
• Theorem on connected sums along (-2)-spheres.