Big $q$-ample Line Bundles
Brown, Morgan V
arXiv, 1105.3449 / Harvested from arXiv
A recent paper of Totaro develops a theory of $q$-ample bundles in characteristic 0. Specifically, a line bundle $L$ on $X$ is $q$-ample if for every coherent sheaf $\mathcal{F}$ on $X$, there exists an integer $m_0$ such that $m\geq m_0$ implies $H^i(X,\mathcal{F}\otimes \mathcal{O}(mL))=0$ for $i>q$. We show that a line bundle $L$ on a complex projective scheme $X$ is $q$-ample if and only if the restriction of $L$ to its augmented base locus is $q$-ample. In particular, when $X$ is a variety and $L$ is big but fails to be $q$-ample, then there exists a codimension 1 subscheme $D$ of $X$ such that the restriction of $L$ to $D$ is not $q$-ample.
Publié le : 2011-05-17
Classification:  Mathematics - Algebraic Geometry,  14C20
@article{1105.3449,
     author = {Brown, Morgan V},
     title = {Big $q$-ample Line Bundles},
     journal = {arXiv},
     volume = {2011},
     number = {0},
     year = {2011},
     language = {en},
     url = {http://dml.mathdoc.fr/item/1105.3449}
}
Brown, Morgan V. Big $q$-ample Line Bundles. arXiv, Tome 2011 (2011) no. 0, . http://gdmltest.u-ga.fr/item/1105.3449/