I'm reading some paper recently. I find a notion which I can not find the exact definition. What is the numerically positive cone in the Neron-Severi group?



What is numerically positive cone
One of the definitions would be the set of real (1,1)-cohomology classes $\alpha$ such that for any analytic cycle $Y\subset X$ of dimension $\dim Y=d$ one has $\int\_Y\alpha^d>0$. A result of Demailly-Paun shows that the Kähler cone is nothing but a connected component of the numerically positive one.


