Gauge theory for embedded surfaces. I
Every 2-dimensional homology class of a closed oriented 4-manifold is represented by an embedded surface. In this paper, the authors give lower bounds on the genus of such a surface in terms of its self-intersection number. They work in a smooth simply-connected 4-manifold which has non- trivial polynomial invariants with \(b_ 2^ +\) odd and not less than 3. As an application, the ``local Thom conjecture'' is solved. It states that if \(C\) is a smooth algebraic curve in complex 2-space and \(B^ 4\) is an embedded 4-ball whose boundary meets \(C\) transversely in a knot \(K\) then the surface \(C\cap B^ 4\) realizes the slice genus of \(K\). This result implies that the unknotting number of a knot which arises from singularities in algebraic curves equals the genus of the Milnor fibre.
scientific article; zbMATH DE number 550344