Computing some fundamental numbers of the variety of nodal cubics in P3

In this paper we obtain some fundamental numbers of the family of non-degenerate nodal cubics in P3 involving, in addition to the characteristic conditions, other fundamental conditions, as for example that the node lies on a plane. Some of these numbers were first obtained by Schubert in his Kalkül der abzählenden Geometrie. In our approach we construct several compactifications of , which can be obtained as a sequence of blow-ups of a suitable projective bundle . We also provide geometric interpretations of the degenerations that appear as exceptional divisors. The computations have been carried out with the Wit system.