On the Nef cones of blowups of the projective plane

In this paper, we study the Cremona action on the Nef cone of $S_n$, the blowup of $\mathbb{P}^2$ in $n$ very general points, with $n\ge9$. We construct and describe a rational polyhedral fundamental domain of the Nef cone for $n=9$ with respect to this action. In the case $n\ge10$, we also give a rational polyhedral fundamental domain of the $K_{S_n}$-negative part of the Nef cone with respect to the Cremona action.
Comment: 16 pages, 3 figures