Fano fourfolds of type A beta

zero loci on products of type A Grassmannians and flag varieties

Family 2-146-36-a

·

No geometric description is recorded for this family (yet).

Defining data
Ambient
Fl(1, 4, 6)
node 1: fundamental weight ω_1 (marked)node 2: fundamental weight ω_2node 3: fundamental weight ω_3node 4: fundamental weight ω_4 (marked)node 5: fundamental weight ω_5ω1ω2ω3ω4ω5
Bundle
E^(w3) + E^(w5) + E^(w1 + w5)
Bundle
wedge^2 U_2^v ot U_3^v + Q_1^v ot wedge^3 U_2^v ot U_3^v + Q_1^v ot wedge^3 U_2^v ot Sym^2 U_3^v
ZL62 label
58.42c
Line bundles on the ambient $Y$
$$\begin{equation} \notag \begin{aligned} \omega_Y^\vee &\cong \mathcal{O}(4,5) \\ \det\mathcal{E} &\cong \mathcal{O}(3,4) \end{aligned} \end{equation}$$
Numerical invariants
Fano index = 1
$\mathrm{h}^0(X, \omega_X^\vee)$ = 36
$\operatorname{vol}(X) = \mathrm{c}_1^4$ = 146
$\chi(X, \mathrm{T}_X)$ = -15

$\omega_X^\vee \cong \mathcal{O}_X(1)$

Chern numbers of $\mathrm{T}_X$
$\mathrm{c}_1^4$ = 146
$\mathrm{c}_1^2\mathrm{c}_2$ = 128
$\mathrm{c}_2^2$ = 114
$\mathrm{c}_1\mathrm{c}_3$ = 32
$\mathrm{c}_4$ = 20
Hodge diamond
1
00
0 2 0
0 0 0 0
0 0 14 0 0
0 0 0 0
0 2 0
00
1
Polyvector parallelogram & Hochschild cohomology
$\mathrm{HH}^{ 0 }$ = 1 1
$\mathrm{HH}^{ 1 }$ = x0 0 x0
$\mathrm{HH}^{ 2 }$ = x0 + x2 + 15 0 x0 + 15 x2
$\mathrm{HH}^{ 3 }$ = x1 + 23 0 0 x1 23
$\mathrm{HH}^{ 4 }$ = x1 - x2 + 27 0 0 x1 - x2 - 9 0 36
$\mathrm{HH}^{ 5 }$ = 0 0 0 0 0
$\mathrm{HH}^{ 6 }$ = 0 0 0 0
$\mathrm{HH}^{ 7 }$ = 0 0 0
$\mathrm{HH}^{ 8 }$ = 0 0

Hilbert series

$\operatorname{Hilb}_X(t)$ $=$
$\displaystyle\frac{ 1 + 31t + 82t^{2} + 31t^{3} + t^{4} }{(1-t)^{ 5 }}$
$=$

Regularized quantum period

Quantum period in the literature

cataloguematching entries
Kalashnikov (2019) CKK(473)
Coates et al. (2020) No match
Coates–Kasprzyk–Prince (2015) No match

Quantum differential equation

With $D=t\frac{\mathrm{d}}{\mathrm{d}t}$, the regularized period satisfies $L_X\widehat{\mathrm{G}}_X=0$.

$$\begin{equation} L_X=\left( t + 1 \right) \left( 2t + 1 \right) \left( 4t^{3} + 12t^{2} + 14t - 1 \right) \left( 108t^{3} + 108t^{2} + 18t + 1 \right) \left( 51938703360t^{13} + 185112594432t^{12} + 298180206720t^{11} + 284423577408t^{10} + 258877249200t^{9} + 253110294576t^{8} + 163864206232t^{7} + 59891307652t^{6} + 11818926044t^{5} + 1252651360t^{4} - 53703714t^{3} + 15415430t^{2} + 244582t + 1241 \right)D^{6} + 2 \left( 381437837475840t^{21} + 3043718203686912t^{20} + 11263894580348928t^{19} + 25381760109972480t^{18} + 39588616406847744t^{17} + 47816209295141760t^{16} + 50281640464460544t^{15} + 48235665950417088t^{14} + 39306302122913280t^{13} + 24648744225800000t^{12} + 11207721722478096t^{11} + 3587726252463224t^{10} + 788087893240960t^{9} + 112500662903660t^{8} + 9573183617480t^{7} + 924147958522t^{6} + 180171021288t^{5} + 10311715165t^{4} - 34501455t^{3} + 30503489t^{2} + 358186t + 1241 \right)D^{5} + \left( 5160629565849600t^{21} + 36908320278675456t^{20} + 122066775852797952t^{19} + 246866194888667136t^{18} + 353553184331753472t^{17} + 414487235850882048t^{16} + 447253985924512704t^{15} + 434526831990793728t^{14} + 338404756544520480t^{13} + 194031399090810640t^{12} + 78940472844208768t^{11} + 22375359582949520t^{10} + 4285412626880928t^{9} + 497211066731152t^{8} + 30011141642932t^{7} + 4621539790872t^{6} + 780825540076t^{5} + 16038574462t^{4} + 853671728t^{3} - 58732166t^{2} - 632933t - 1241 \right)D^{4} + 2 t \left( 8862820341350400t^{20} + 57881168146022400t^{19} + 175172716774840320t^{18} + 325930461864477696t^{17} + 441320907484880640t^{16} + 518465042487599616t^{15} + 576625996418028480t^{14} + 554497176199344768t^{13} + 406900632557848128t^{12} + 214260601004292688t^{11} + 79363942223060112t^{10} + 20492457691020424t^{9} + 3570737236508880t^{8} + 376506851170092t^{7} + 34212811582528t^{6} + 8180656545458t^{5} + 867024126594t^{4} + 21737862567t^{3} + 337756835t^{2} + 2031945t + 527 \right)D^{3} + 4 t ^{2} \left( 8122382186250240t^{19} + 49325884365570048t^{18} + 139433715243270144t^{17} + 243422743107179520t^{16} + 318348866744830080t^{15} + 380788406132683392t^{14} + 432580768590229776t^{13} + 405784802124805536t^{12} + 280438950279178584t^{11} + 137191723875923580t^{10} + 47189233678137400t^{9} + 11416816178329032t^{8} + 1871025255368144t^{7} + 192751066219292t^{6} + 27114846091802t^{5} + 6042667200328t^{4} + 434426696764t^{3} + 9338995322t^{2} + 145560308t + 810957 \right)D^{2} + 8 t ^{2} \left( 3747065815203840t^{19} + 21514222986412032t^{18} + 57787422549792768t^{17} + 96167674969721856t^{16} + 123286888980011520t^{15} + 150911180637973632t^{14} + 173361826895361840t^{13} + 157833368268327936t^{12} + 103357903729420776t^{11} + 47596560862088196t^{10} + 15489905939820168t^{9} + 3598435232366440t^{8} + 570725239165408t^{7} + 62241361104720t^{6} + 11882275437826t^{5} + 2205565603466t^{4} + 115957317082t^{3} + 2436636605t^{2} + 33630055t + 161330 \right)D + 32 t ^{2} \left( 336562797772800t^{19} + 1854529651556352t^{18} + 4801338401439744t^{17} + 7716654494277120t^{16} + 9789338522124864t^{15} + 12245658890423040t^{14} + 14128299654636240t^{13} + 12503980712715120t^{12} + 7830704052705816t^{11} + 3438630919869108t^{10} + 1075822363340680t^{9} + 244350211015044t^{8} + 38209309497308t^{7} + 4590353849262t^{6} + 1030471265474t^{5} + 159426604290t^{4} + 6547018206t^{3} + 143649282t^{2} + 1666816t + 6205 \right) \notag \end{equation}$$

Quantum spectrum

Ambient: Fl(1, 4, 6)

|λ| = 14.8275 λ ≈ 14.8275; multiplicity 1; Jordan blocks 1 λ ≈ -8.381102 - 4.124189i; multiplicity 1; Jordan blocks 1 λ ≈ -8.381102 + 4.124189i; multiplicity 1; Jordan blocks 1 λ ≈ -2; multiplicity 1; Jordan blocks 1 λ ≈ -1.237797; multiplicity 1; Jordan blocks 1 λ ≈ -1; multiplicity 2; Jordan blocks 1, 1 λ ≈ -0.4137504 - 0.3139739i; multiplicity 1; Jordan blocks 1 λ ≈ -0.4137504 + 0.3139739i; multiplicity 1; Jordan blocks 1 λ ≈ 0; multiplicity 1; Jordan blocks 1 2
Sector dimension
10
Spectral radius
$14.8275008$
Diagonalizable at 1
Yes
Simple spectrum at 1
No
Eigenvalue approximations and Jordan block sizes
eigenvaluemultiplicityJordan blocks
$14.8275$11
$-8.381102 - 4.124189\mathrm{i}$11
$-8.381102 + 4.124189\mathrm{i}$11
$-2$11
$-1.237797$11
$-1$21, 1
$-0.4137504 - 0.3139739\mathrm{i}$11
$-0.4137504 + 0.3139739\mathrm{i}$11
$0$11

Characteristic polynomial

$$\begin{equation}\lambda \left(\lambda + 1\right)^{2} \left(\lambda + 2\right) \left(\lambda^{3} + 18 \lambda^{2} + 108 \lambda + 108\right) \left(\lambda^{3} - 14 \lambda^{2} - 12 \lambda - 4\right)\notag\end{equation}$$

Minimal polynomial

$$\begin{equation}\lambda \left(\lambda + 1\right) \left(\lambda + 2\right) \left(\lambda^{3} + 18 \lambda^{2} + 108 \lambda + 108\right) \left(\lambda^{3} - 14 \lambda^{2} - 12 \lambda - 4\right)\notag\end{equation}$$

Quantum multiplication matrix

$$\begin{equation}\begin{pmatrix}0 & 10 & 10 & 48 & 24 & 39 & 27 & 108 & 76 & 250 \\ 1 & -1 & 3 & 4 & 8 & 0 & 0 & 57 & 39 & 20 \\ 1 & 1 & -1 & 20 & 12 & 14 & 10 & 18 & 12 & 60 \\ 0 & 1 & 1 & -2 & -2 & 0 & 0 & 2 & 2 & 15 \\ 0 & 1 & 0 & 3 & 0 & 3 & 2 & 0 & 0 & 15 \\ 0 & 0 & 1 & 1 & 2 & -1 & 0 & 12 & 8 & 0 \\ 0 & 0 & 1 & 1 & 2 & 0 & -1 & 12 & 8 & 0 \\ 0 & 0 & 0 & -4 & -12 & \frac{9}{2} & \frac{5}{2} & -\frac{39}{2} & -\frac{23}{2} & 25 \\ 0 & 0 & 0 & 10 & 20 & -\frac{7}{2} & -\frac{3}{2} & \frac{59}{2} & \frac{35}{2} & -25 \\ 0 & 0 & 0 & 0 & 0 & 0 & 0 & \frac{13}{5} & \frac{9}{5} & 0\end{pmatrix}\notag\end{equation}$$