For any negative definite plumbed 3-manifold M we construct from its plumbed graph a graded Z[U ]-module. This, for rational homology spheres, conjecturally equals the Heegaard-Floer homology of Ozsváth and Szabó, but it has even more structure. If M is a complex singularity link then the normalized Euler-characteristic can be compared with the analytic invariants. The Seiberg-Witten Invariant Conjecture of [16], [13] is discussed in the light of this new object.
§1. IntroductionThe article is a symbiosis of singularity theory and low-dimensional topology. Accordingly, it is preferable to separate its goals in two categories.From the point of view of 3-dimensional topology, the article contains the following main result. For every negative definite plumbed 3-manifold it constructs a graded Z[U ]-module from the combinatorics of the plumbing graph. This for rational homology spheres conjecturally equals the Heegaard-Floer homology of Ozsváth and Szabó. In fact, it has more structure (e.g. instead of a