del Pezzo surface: $\mathrm{Bl}_4\mathbb{P}^2$
Identification
$\mathrm{Bl}_3\mathbb{P}^2$ $\mathrm{Bl}_5\mathbb{P}^2$
del Pezzo surface $\mathrm{Bl}_4\mathbb{P}^2$
- Picard rank
- 5
- $-\mathrm{K}_S^2$
- 5
- alternatives
-
divisor of degree $(1,2)$ in $\mathbb{P}^1\times\mathbb{P}^2$
section of $\mathrm{Gr}(2,5)$ in $\mathbb{P}^9$ by a codimension 4 linear subspace
Hodge diamond
1
0 0
0 5 0
0 0
1
0 0
0 5 0
0 0
1
Anticanonical bundle
- index
- 1
- $\dim\mathrm{H}^0(S,\omega_S^\vee)$
- 6
- $-\mathrm{K}_S$ very ample?
- yes
Deformation theory
- number of moduli
- 0
- Bott vanishing
- holds
Automorphism groups
group | dimension | |
$\mathrm{Sym}_5$ | 0 |