6 papers
Fano manifolds with long extremal rays
Marco Andreatta, Gianluca Occhetta
Let X be a Fano manifold of pseudoindex i_X whose Picard number is at least two and let R be an extremal ray of X with exceptional locus Exc(R). We prove an inequality which bounds…
Generalized Mukai conjecture for special Fano varieties
Marco Andreatta, Elena Chierici, Gianluca Occhetta
Let X be a Fano variety of dimension n, pseudoindex i_X and Picard number ρ_X. A generalization of a conjecture of Mukai says that ρ_X(i_X-1)\le n. We prove that the conjecture hol…
Characterization theorems for the projective space and vector bundle adjunction
Marco Andreatta
We consider some conditions under which a smooth projective variety X is actually the projective space. We also extend to the case of positive characteristic some results in the th…
Morphisms of Projective Varieties from the viewpoint of Minimal Model Theory
M. Andreatta, M. Mella
In this Lecture Notes we present, in a sufficiently self contained way, our contributions and interests in the field of Minimal Model Theory. We study Fano-Mori spaces, both from t…
Special rays in the Mori cone of a projective variety
Marco Andreatta, Gianluca Occhetta
Let be a smooth -dimensional projective variety over an algebraically closed field such that is not nef. We give a characterization of non nef extremal rays of …
Actions of Linear Algebraic Groups on Projective Manifolds and Minimal Model Program
Marco Andreatta
Let X be a smooth projective variety of dimension n on which a simple Lie group G acts regularly and non trivially. Then X is not minimal in the sense of the Minimal Model Program.…