0

On a Moishezon manifold,is a big line bundle nef?Why?

flag
4 
Terminology? Motivation? Anything? – David Hansen May 24 2011 at 1:25
3 
Why would it be? Being big is very much a birational notion. Being nef is very much not. – Sándor Kovács May 24 2011 at 1:35
3 
p.s.: By the way, let $B$ be an arbitrary big line bundle and $E$ an arbitrary line bundle that has a global section, but which is not nef (i.e., there exists a (compact) curve $C$ such that $E|_C$ has negative degree). Then $B\otimes E^{\otimes m}$ is big for any $m\geq 0$, but not nef for $m\gg 0$. This works on any manifold/variety/scheme/space when the notions big and nef make sense. – Sándor Kovács May 24 2011 at 4:21

closed as not a real question by Ryan Budney, Will Jagy, Andy Putman, David Hansen, Charles Siegel May 24 2011 at 12:52

Browse other questions tagged or ask your own question.