Sulla razionalità dei piani doppi e tripli ciclici
Explicit resolutions of double point singularities of surfaces.
Locally analytically, any isolated double point occurs as a double cover of a smooth surface. It can be desingularized explicitly via the canonical resolution, as it is very well-known. In this paper we explicitly compute the fundamental cycle of both the canonical and minimal resolution of a double point singularity and we classify those for which the fundamental cycle differs from the fiber cycle. Moreover we compute the conditions that a double point singularity imposes to pluricanonical systems....
Examples of threefolds with Kodaira dimension 1 or 2
On the genus of reducible surfaces and degenerations of surfaces
We deal with a reducible projective surface with so-called , which are a generalization of normal crossings. First we compute the of , i.e. the dimension of the vector space of global sections of the dualizing sheaf . Then we prove that, when is smoothable, i.e. when is the central fibre of a flat family parametrized by a disc, with smooth general fibre, then the -genus of the fibres of is constant.
On special projections of varieties: Epitome to a theorem of Beniamino Segre.
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