del Pezzo surface: $\mathrm{Bl}_2\mathbb{P}^2$
Identification
$\mathrm{Bl}_1\mathbb{P}^2$ $\mathrm{Bl}_3\mathbb{P}^2$
del Pezzo surface $\mathrm{Bl}_2\mathbb{P}^2$
- Picard rank
- 3
- $-\mathrm{K}_S^2$
- 7
- alternatives
- complete intersection of $(1,0,1)$- and $(0,1,1)$-divisor in $\mathbb{P}^1\times\mathbb{P}^1\times\mathbb{P}^2$
Hodge diamond
1
0 0
0 3 0
0 0
1
0 0
0 3 0
0 0
1
Anticanonical bundle
- index
- 1
- $\dim\mathrm{H}^0(S,\omega_S^\vee)$
- 8
- $-\mathrm{K}_S$ very ample?
- yes
Deformation theory
- number of moduli
- 0
- Bott vanishing
- holds
Automorphism groups
group | dimension | |
$\left\{ \Bigl( \begin{smallmatrix} 1 & 0 & * \\ 0 & * & * \\ 0 & 0 & * \end{smallmatrix} \Bigr) \right\}\rtimes\mathrm{Sym}_2$ | 4 |