an overview of the literature listing Fano fourfolds
Hausen, J., Laface, A., & Mauz, C. (2022). On smooth Fano fourfolds of Picard number two. Rev. Mat. Iberoam., 38(1), 53–93.
| count | 67 families |
|---|---|
| construction | cox-ring-hypersurface |
| Picard rank $\rho_X$ | 2 |
| entry numbering | Table 1 row (No.) |
| invariants | hodge, volume, hilbert_series, contractions |
| links | 10.4171/rmi/1271 MR4382464 |
| notes | 67 smooth Fano fourfolds of Picard number two with a general hypersurface Cox ring (Theorem 1.1). Elementary contractions (Proposition 6.2), Hodge numbers (Propositions 7.1–7.2), volumes and Hilbert series provided. |
Each row is a family from this source. The description column records the construction as given in the paper (ambient and defining bundle, Cox-ring data, base variety, or birational model, depending on the source); the invariant columns are those the paper tabulates. Provenance and conventions are noted below the table.
How to read the construction. Each family is a general hypersurface in a toric variety of Picard number two. Its Cox ring is a polynomial ring in seven variables graded by the divisor class group $\mathbb{Z}^2$; the two rows of the matrix $w$ are the $\mathbb{Z}^2$-degrees of those seven generators. The fourfold $X$ is cut out by a general polynomial $g$ of bidegree $\deg(g)$, and $-K$ is its anticanonical class in $\mathbb{Z}^2$; the volume is $(-K)^4$. In short: $X=\{g=0\}$ inside the toric variety whose homogeneous coordinates carry the degrees $w$.
| entry | $\rho_X$ | $(-\mathrm{K}_X)^4$ | $\mathrm{h}^{1,1}$ | $\mathrm{h}^{1,2}$ | $\mathrm{h}^{1,3}$ | $\mathrm{h}^{2,2}$ | description |
|---|---|---|---|---|---|---|---|
| HLM22:1 | 2 | 432 | 2 | 0 | 0 | 3 | w=[[1,1,1,1,0,0,0],[0,0,0,0,1,1,1]]; deg(g)=(1,1); -K=(3,2) |
| HLM22:2 | 2 | 256 | 2 | 0 | 0 | 10 | w=[[1,1,1,1,0,0,0],[0,0,0,0,1,1,1]]; deg(g)=(2,1); -K=(2,2) |
| HLM22:3 | 2 | 80 | 2 | 0 | 0 | 29 | w=[[1,1,1,1,0,0,0],[0,0,0,0,1,1,1]]; deg(g)=(3,1); -K=(1,2) |
| HLM22:4 | 2 | 270 | 2 | 0 | 0 | 3 | w=[[1,1,1,1,0,0,0],[0,0,0,0,1,1,1]]; deg(g)=(1,2); -K=(3,1) |
| HLM22:5 | 2 | 112 | 2 | 0 | 3 | 40 | w=[[1,1,1,1,0,0,0],[0,0,0,0,1,1,1]]; deg(g)=(2,2); -K=(2,1) |
| HLM22:6 | 2 | 26 | 2 | 0 | 30 | 185 | w=[[1,1,1,1,0,0,0],[0,0,0,0,1,1,1]]; deg(g)=(3,2); -K=(1,1) |
| HLM22:7 | 2 | 416 | 2 | 0 | 0 | 4 | w=[[1,1,1,1,0,0,-1],[0,0,0,0,1,1,1]]; deg(g)=(1,1); -K=(2,2) |
| HLM22:8 | 2 | 163 | 2 | 0 | 1 | 23 | w=[[1,1,1,1,0,0,-1],[0,0,0,0,1,1,1]]; deg(g)=(1,2); -K=(2,1) |
| HLM22:9 | 2 | 224 | 2 | 0 | 0 | 14 | w=[[1,1,1,1,0,0,-1],[0,0,0,0,1,1,1]]; deg(g)=(2,1); -K=(1,2) |
| HLM22:10 | 2 | 52 | 2 | 0 | 18 | 126 | w=[[1,1,1,1,0,0,-1],[0,0,0,0,1,1,1]]; deg(g)=(2,2); -K=(1,1) |
| HLM22:11 | 2 | 464 | 2 | 0 | 0 | 5 | w=[[1,1,1,1,0,0,-2],[0,0,0,0,1,1,1]]; deg(g)=(1,1); -K=(1,2) |
| HLM22:12 | 2 | 98 | 2 | 0 | 12 | 95 | w=[[1,1,1,1,0,0,-2],[0,0,0,0,1,1,1]]; deg(g)=(1,2); -K=(1,1) |
| HLM22:13 | 2 | 352 | 2 | 0 | 0 | 4 | w=[[1,1,1,1,0,0,0],[0,0,0,1,1,1,1]]; deg(g)=(1,2); -K=(3,2) |
| HLM22:14 | 2 | 65 | 2 | 0 | 6 | 65 | w=[[1,1,1,1,0,0,0],[0,0,0,1,1,1,1]]; deg(g)=(2,3); -K=(2,1) |
| HLM22:15 | 2 | 83 | 2 | 0 | 5 | 55 | w=[[1,1,1,1,0,0,-1],[0,0,0,1,1,1,1]]; deg(g)=(1,3); -K=(2,1) |
| HLM22:16 | 2 | 352 | 2 | 0 | 0 | 6 | w=[[1,1,1,1,1,0,0],[0,0,0,0,1,1,1]]; deg(g)=(2,1); -K=(3,2) |
| HLM22:17 | 2 | 81 | 2 | 0 | 9 | 77 | w=[[1,1,1,1,1,0,0],[0,0,0,0,1,1,1]]; deg(g)=(3,2); -K=(2,1) |
| HLM22:18 | 2 | 38 | 2 | 0 | 21 | 143 | w=[[1,1,1,1,1,0,0],[0,0,0,0,1,1,1]]; deg(g)=(3,1); -K=(1,1) |
| HLM22:19 | 2 | 192 | 2 | 0 | 1 | 22 | w=[[1,1,1,1,0,0,0],[-1,0,0,0,1,1,1]]; deg(g)=(2,1); -K=(2,1) |
| HLM22:20 | 2 | 432 | 2 | 0 | 0 | 3 | w=[[1,1,1,1,0,0,0],[-1,0,0,0,1,1,1]]; deg(g)=(1,1); -K=(3,1) |
| HLM22:21 | 2 | 113 | 2 | 0 | 5 | 53 | w=[[1,1,1,1,1,0,0],[-1,0,0,0,1,1,1]]; deg(g)=(3,1); -K=(2,1) |
| HLM22:22 | 2 | 272 | 2 | 0 | 0 | 10 | w=[[1,1,1,1,0,0,0],[0,0,1,1,1,1,1]]; deg(g)=(2,2); -K=(2,3) |
| HLM22:23 | 2 | 51 | 2 | 0 | 13 | 103 | w=[[1,1,1,1,0,0,0],[0,0,1,1,1,1,1]]; deg(g)=(3,3); -K=(1,2) |
| HLM22:24 | 2 | 34 | 2 | 0 | 35 | 218 | w=[[1,1,1,2,0,0,0],[0,0,1,2,1,1,1]]; deg(g)=(4,4); -K=(1,2) |
| HLM22:25 | 2 | 17 | 2 | 0 | 114 | 591 | w=[[1,1,2,3,0,0,0],[0,0,2,3,1,1,1]]; deg(g)=(6,6); -K=(1,2) |
| HLM22:26 | 2 | 216 | 2 | 0 | 0 | 10 | w=[[1,1,1,0,0,0,0],[0,0,1,1,1,1,1]]; deg(g)=(2,2); -K=(1,3) |
| HLM22:27 | 2 | 64 | 2 | 0 | 20 | 138 | w=[[1,1,1,0,0,0,0],[0,0,2,1,1,1,1]]; deg(g)=(2,4); -K=(1,2) |
| HLM22:28 | 2 | 8 | 2 | 0 | 112 | 570 | w=[[1,1,1,0,0,0,0],[0,0,3,1,1,1,1]]; deg(g)=(2,6); -K=(1,1) |
| HLM22:29 | 2 | 192 | 2 | 0 | 1 | 22 | w=[[1,1,1,1,0,0,0],[0,0,0,1,1,1,1]]; deg(g)=(2,2); -K=(2,2) |
| HLM22:30 | 2 | 18 | 2 | 0 | 45 | 255 | w=[[1,1,1,1,0,0,0],[0,0,0,1,1,1,1]]; deg(g)=(3,3); -K=(1,1) |
| HLM22:31 | 2 | 48 | 2 | 0 | 10 | 94 | w=[[1,1,1,2,0,0,0],[0,0,0,1,1,1,1]]; deg(g)=(4,2); -K=(1,2) |
| HLM22:32 | 2 | 12 | 2 | 0 | 100 | 508 | w=[[1,1,1,2,0,0,0],[0,0,0,2,1,1,1]]; deg(g)=(4,4); -K=(1,1) |
| HLM22:33 | 2 | 50 | 2 | 0 | 24 | 162 | w=[[1,1,2,1,0,0,0],[0,1,3,2,1,1,1]]; deg(g)=(4,6); -K=(1,3) |
| HLM22:34 | 2 | 378 | 2 | 0 | 0 | 4 | w=[[1,1,1,1,1,0,0],[0,1,1,1,1,1,1]]; deg(g)=(2,2); -K=(3,4) |
| HLM22:35 | 2 | 144 | 2 | 0 | 1 | 28 | w=[[1,1,1,1,1,0,0],[0,1,1,1,1,1,1]]; deg(g)=(3,3); -K=(2,3) |
| HLM22:36 | 2 | 20 | 2 | 0 | 22 | 162 | w=[[1,1,1,1,1,0,0],[0,1,1,1,1,1,1]]; deg(g)=(4,4); -K=(1,2) |
| HLM22:37 | 2 | 96 | 2 | 0 | 5 | 60 | w=[[1,1,1,1,2,0,0],[0,1,1,1,2,1,1]]; deg(g)=(4,4); -K=(2,3) |
| HLM22:38 | 2 | 10 | 2 | 0 | 71 | 402 | w=[[1,1,1,1,3,0,0],[0,1,1,1,3,1,1]]; deg(g)=(6,6); -K=(1,2) |
| HLM22:39 | 2 | 48 | 2 | 0 | 24 | 170 | w=[[1,1,1,2,3,0,0],[0,1,1,2,3,1,1]]; deg(g)=(6,6); -K=(2,3) |
| HLM22:40 | 2 | 352 | 2 | 0 | 0 | 4 | w=[[1,1,1,1,0,0,0],[0,1,1,1,1,1,1]]; deg(g)=(2,2); -K=(2,4) |
| HLM22:41 | 2 | 99 | 2 | 1 | 1 | 23 | w=[[1,1,1,1,0,0,0],[0,1,1,1,1,1,1]]; deg(g)=(3,3); -K=(1,3) |
| HLM22:42 | 2 | 304 | 2 | 0 | 0 | 10 | w=[[1,1,1,1,0,0,0],[0,2,2,2,1,1,1]]; deg(g)=(2,4); -K=(2,5) |
| HLM22:43 | 2 | 54 | 2 | 1 | 19 | 131 | w=[[1,1,1,1,0,0,0],[0,2,2,2,1,1,1]]; deg(g)=(3,6); -K=(1,3) |
| HLM22:44 | 2 | 66 | 2 | 1 | 5 | 54 | w=[[1,1,1,2,0,0,0],[0,1,1,2,1,1,1]]; deg(g)=(4,4); -K=(1,3) |
| HLM22:45 | 2 | 36 | 2 | 1 | 50 | 288 | w=[[1,1,1,2,0,0,0],[0,2,2,4,1,1,1]]; deg(g)=(4,8); -K=(1,3) |
| HLM22:46 | 2 | 33 | 2 | 1 | 24 | 163 | w=[[1,1,2,3,0,0,0],[0,1,2,3,1,1,1]]; deg(g)=(6,6); -K=(1,3) |
| HLM22:47 | 2 | 18 | 2 | 1 | 159 | 793 | w=[[1,1,2,3,0,0,0],[0,2,4,6,1,1,1]]; deg(g)=(6,12); -K=(1,3) |
| HLM22:48 | 2 | 433 | 2 | 0 | 0 | 3 | w=[[1,1,1,1,1,0,0],[0,1,1,1,2,1,1]]; deg(g)=(2,2); -K=(3,5) |
| HLM22:49 | 2 | 145 | 2 | 1 | 2 | 31 | w=[[1,1,1,1,1,0,0],[0,2,2,2,3,1,1]]; deg(g)=(3,6); -K=(2,5) |
| HLM22:50 | 2 | 144 | 2 | 0 | 3 | 40 | w=[[1,1,1,1,0,0,0],[0,1,1,2,1,1,1]]; deg(g)=(2,4); -K=(2,3) |
| HLM22:51 | 2 | 22 | 2 | 0 | 65 | 356 | w=[[1,1,1,2,0,0,0],[0,1,1,3,1,1,1]]; deg(g)=(4,6); -K=(1,2) |
| HLM22:52 | 2 | 65 | 2 | 0 | 20 | 139 | w=[[1,1,1,2,1,0,0],[0,1,1,3,2,1,1]]; deg(g)=(4,6); -K=(2,3) |
| HLM22:53 | 2 | 431 | 2 | 0 | 0 | 3 | w=[[1,1,1,1,1,1,0],[-1,0,0,0,0,1,1]]; deg(g)=(2,0); -K=(4,1) |
| HLM22:54 | 2 | 62 | 2 | 0 | 6 | 72 | w=[[1,1,1,1,1,1,0],[-1,0,0,0,0,1,1]]; deg(g)=(4,0); -K=(2,1) |
| HLM22:55 | 2 | 376 | 2 | 0 | 0 | 8 | w=[[1,1,1,1,1,2,0],[-1,0,0,0,0,1,1]]; deg(g)=(3,0); -K=(4,1) |
| HLM22:56 | 2 | 341 | 2 | 0 | 1 | 21 | w=[[1,1,1,1,1,3,0],[-1,0,0,0,0,1,1]]; deg(g)=(4,0); -K=(4,1) |
| HLM22:57 | 2 | 31 | 2 | 0 | 25 | 181 | w=[[1,1,1,1,3,1,0],[-1,0,0,0,0,1,1]]; deg(g)=(6,0); -K=(2,1) |
| HLM22:58 | 2 | 16 | 2 | 52 | 0 | 2 | w=[[1,1,1,1,3,0,0],[0,0,0,0,0,1,1]]; deg(g)=(6,0); -K=(1,2) |
| HLM22:59 | 2 | 64 | 2 | 21 | 0 | 2 | w=[[1,1,1,2,3,0,0],[0,0,0,0,0,1,1]]; deg(g)=(6,0); -K=(2,2) |
| HLM22:60 | 2 | 80 | 2 | 21 | 0 | 2 | w=[[1,1,1,2,3,1,0],[0,0,0,0,0,1,1]]; deg(g)=(6,0); -K=(3,2) |
| HLM22:61 | 2 | 128 | 2 | 10 | 0 | 2 | w=[[1,1,1,1,2,0,0],[0,0,0,0,0,1,1]]; deg(g)=(4,0); -K=(2,2) |
| HLM22:62 | 2 | 160 | 2 | 10 | 0 | 2 | w=[[1,1,1,1,2,1,0],[0,0,0,0,0,1,1]]; deg(g)=(4,0); -K=(3,2) |
| HLM22:63 | 2 | 192 | 2 | 5 | 0 | 2 | w=[[1,1,1,1,1,0,0],[0,0,0,0,0,1,1]]; deg(g)=(3,0); -K=(2,2) |
| HLM22:64 | 2 | 240 | 2 | 5 | 0 | 2 | w=[[1,1,1,1,1,1,0],[0,0,0,0,0,1,1]]; deg(g)=(3,0); -K=(3,2) |
| HLM22:65 | 2 | 432 | 2 | 0 | 0 | 2 | w=[[1,1,1,1,1,0,0],[0,0,0,0,0,1,1]]; deg(g)=(2,0); -K=(3,2) |
| HLM22:66 | 2 | 480 | 2 | 0 | 0 | 2 | w=[[1,1,1,1,1,1,0],[0,0,0,0,0,1,1]]; deg(g)=(2,0); -K=(4,2) |
| HLM22:67 | 2 | 624 | 2 | 0 | 0 | 2 | w=[[1,1,1,1,1,2,0],[0,0,0,0,0,1,1]]; deg(g)=(2,0); -K=(5,2) |
Volumes from Theorem 1.1; Hodge numbers from Proposition 7.2. Numbering follows the paper's Table 1 (No. 1-67). Source: arXiv:1907.08000.