%0 Journal Article
%T Special rays in the Mori cone of a projective variety
%A Marco Andreatta
%A Gianluca Occhetta
%J Mathematics
%D 2000
%I arXiv
%X Let $X$ be a smooth $n$-dimensional projective variety over an algebraically closed field $k$ such that $K_X$ is not nef. We give a characterization of non nef extremal rays of $X$ of maximal length (i.e of length $n-1$); in the case of $\ch(k) = 0$ we also characterize non nef rays of length $n-2$.
%U http://arxiv.org/abs/math/0010101v1