Properties

Label 36.216.2-18.d.1.12
Level $36$
Index $216$
Genus $2$
Analytic rank $0$
Cusps $16$
$\Q$-cusps $6$

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Invariants

Level: $36$ $\SL_2$-level: $36$ Newform level: $18$
Index: $216$ $\PSL_2$-index:$108$
Genus: $2 = 1 + \frac{ 108 }{12} - \frac{ 0 }{4} - \frac{ 0 }{3} - \frac{ 16 }{2}$
Cusps: $16$ (of which $6$ are rational) Cusp widths $1^{3}\cdot2^{3}\cdot3^{2}\cdot6^{2}\cdot9^{3}\cdot18^{3}$ Cusp orbits $1^{6}\cdot2^{2}\cdot3^{2}$
Elliptic points: $0$ of order $2$ and $0$ of order $3$
Analytic rank: $0$
$\Q$-gonality: $2$
$\overline{\Q}$-gonality: $2$
Rational cusps: $6$
Rational CM points: none

Other labels

Cummins and Pauli (CP) label: 18Q2
Rouse, Sutherland, and Zureick-Brown (RSZB) label: 36.216.2.36

Level structure

$\GL_2(\Z/36\Z)$-generators: $\begin{bmatrix}17&22\\18&29\end{bmatrix}$, $\begin{bmatrix}19&10\\18&35\end{bmatrix}$, $\begin{bmatrix}19&34\\0&5\end{bmatrix}$, $\begin{bmatrix}35&1\\18&35\end{bmatrix}$
$\GL_2(\Z/36\Z)$-subgroup: $D_{18}:(C_6\times D_4)$
Contains $-I$: no $\quad$ (see 18.108.2.d.1 for the level structure with $-I$)
Cyclic 36-isogeny field degree: $2$
Cyclic 36-torsion field degree: $8$
Full 36-torsion field degree: $1728$

Jacobian

Conductor: $2^{2}\cdot3^{4}$
Simple: yes
Squarefree: yes
Decomposition: $2$
Newforms: 18.2.c.a

Models

Embedded model Embedded model in $\mathbb{P}^{3}$

$ 0 $ $=$ $ x y z - x z^{2} - x z w - y^{2} z + y z^{2} - z^{3} + z w^{2} $
$=$ $x y^{2} - x y z - x y w - y^{3} + y^{2} z - y z^{2} + y w^{2}$
$=$ $x y w - x z w - x w^{2} - y^{2} w + y z w - z^{2} w + w^{3}$
$=$ $x^{2} y - x^{2} z - x^{2} w - x y^{2} + x y z - x z^{2} + x w^{2}$
$=$$\cdots$
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Singular plane model Singular plane model

$ 0 $ $=$ $ 2 x^{3} y - x^{3} z - 2 x^{2} y^{2} + 4 x^{2} y z - 2 x^{2} z^{2} + 2 x y^{3} - 3 x y^{2} z + \cdots - y^{2} z^{2} $
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Weierstrass model Weierstrass model

$ y^{2} + \left(x^{3} + x + 1\right) y $ $=$ $ x^{5} + 2x^{4} + 2x^{3} + x^{2} $
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Rational points

This modular curve has 6 rational cusps but no known non-cuspidal rational points. The following are the coordinates of the rational cusps on this modular curve.

Embedded model
$(1:1:0:0)$, $(1:0:0:0)$, $(-1:0:1:0)$, $(1:0:0:1)$, $(1:0:-1:1)$, $(1:1:0:1)$

Maps to other modular curves

$j$-invariant map of degree 108 from the embedded model of this modular curve to the modular curve $X(1)$ :

$\displaystyle j$ $=$ $\displaystyle 2\,\frac{524288x^{22}-13369344x^{21}w+162398208x^{20}w^{2}-1248067584x^{19}w^{3}+6797721600x^{18}w^{4}-27854143488x^{17}w^{5}+88955633664x^{16}w^{6}-226326085632x^{15}w^{7}+464931145728x^{14}w^{8}-776783047680x^{13}w^{9}+1058044626432x^{12}w^{10}-1172523368448x^{11}w^{11}+1050374939904x^{10}w^{12}-751997748096x^{9}w^{13}+422830290240x^{8}w^{14}-182040225984x^{7}w^{15}+57839562432x^{6}w^{16}-12832557840x^{5}w^{17}+1815916752x^{4}w^{18}-138313980x^{3}w^{19}+3957903x^{2}w^{20}-191102976xz^{20}w-764411904xz^{19}w^{2}-47775744xz^{18}w^{3}+4825350144xz^{17}w^{4}+10809262080xz^{16}w^{5}+9029615616xz^{15}w^{6}-964472832xz^{14}w^{7}-8192047104xz^{13}w^{8}-6631870464xz^{12}w^{9}-1492535808xz^{11}w^{10}+1334444544xz^{10}w^{11}+1322002944xz^{9}w^{12}+437439744xz^{8}w^{13}-39788928xz^{7}w^{14}-89098272xz^{6}w^{15}-37439280xz^{5}w^{16}-4240296xz^{4}w^{17}+1441908xz^{3}w^{18}+838566xz^{2}w^{19}+1236762xzw^{20}+613926xw^{21}-573308928yz^{19}w^{2}-3009871872yz^{18}w^{3}-5709201408yz^{17}w^{4}-3069591552yz^{16}w^{5}+4843266048yz^{15}w^{6}+8859414528yz^{14}w^{7}+4793997312yz^{13}w^{8}-863695872yz^{12}w^{9}-2601828864yz^{11}w^{10}-1460851200yz^{10}w^{11}-159252480yz^{9}w^{12}+259887744yz^{8}w^{13}+151488576yz^{7}w^{14}+29461536yz^{6}w^{15}-5782320yz^{5}w^{16}-5846040yz^{4}w^{17}+295596yz^{3}w^{18}+189054yz^{2}w^{19}-288603yzw^{20}-191102976z^{21}w-573308928z^{20}w^{2}+1051066368z^{19}w^{3}+6688604160z^{18}w^{4}+9519316992z^{17}w^{5}+41803776z^{16}w^{6}-13616087040z^{15}w^{7}-13789274112z^{14}w^{8}-2026736640z^{13}w^{9}+5898147840z^{12}w^{10}+4935043584z^{11}w^{11}+1160428032z^{10}w^{12}-763713792z^{9}w^{13}-699198912z^{8}w^{14}-178318368z^{7}w^{15}+28012176z^{6}w^{16}+38673720z^{5}w^{17}+11160180z^{4}w^{18}-898938z^{3}w^{19}-79461z^{2}w^{20}-948159zw^{21}-402489w^{22}}{w^{7}(4x^{4}w^{11}-30x^{3}w^{12}+87x^{2}w^{13}-221184xz^{14}-1105920xz^{13}w-1935360xz^{12}w^{2}-850944xz^{11}w^{3}+1526784xz^{10}w^{4}+2215680xz^{9}w^{5}+949888xz^{8}w^{6}-51200xz^{7}w^{7}-137152xz^{6}w^{8}-23600xz^{5}w^{9}+1048xz^{4}w^{10}-4xz^{3}w^{11}+16xz^{2}w^{12}+28xzw^{13}-100xw^{14}+221184yz^{14}+552960yz^{13}w-221184yz^{12}w^{2}-1929216yz^{11}w^{3}-2070528yz^{10}w^{4}-446976yz^{9}w^{5}+515968yz^{8}w^{6}+298688yz^{7}w^{7}+20608yz^{6}w^{8}-9280yz^{5}w^{9}+40yz^{4}w^{10}-28yz^{3}w^{11}+18yz^{2}w^{12}-21yzw^{13}-221184z^{15}-995328z^{14}w-1105920z^{13}w^{2}+1305600z^{12}w^{3}+3743232z^{11}w^{4}+2204928z^{10}w^{5}-926336z^{9}w^{6}-1440320z^{8}w^{7}-358496z^{7}w^{8}+91664z^{6}w^{9}+34040z^{5}w^{10}-1140z^{4}w^{11}+48z^{3}w^{12}-27z^{2}w^{13}-7zw^{14}+39w^{15})}$

Map of degree 1 from the embedded model of this modular curve to the plane model of the modular curve $X_{\pm1}(18)$ :

$\displaystyle X$ $=$ $\displaystyle z$
$\displaystyle Y$ $=$ $\displaystyle y$
$\displaystyle Z$ $=$ $\displaystyle w$

Equation of the image curve:

$0$ $=$ $ 2X^{3}Y-2X^{2}Y^{2}+2XY^{3}-X^{3}Z+4X^{2}YZ-3XY^{2}Z+Y^{3}Z-2X^{2}Z^{2}+2XYZ^{2}-Y^{2}Z^{2}-XZ^{3} $

Map of degree 1 from the embedded model of this modular curve to the Weierstrass model of the modular curve $X_{\pm1}(18)$ :

$\displaystyle X$ $=$ $\displaystyle -y$
$\displaystyle Y$ $=$ $\displaystyle y^{2}z+y^{2}w-2yz^{2}-4yzw-2yw^{2}+z^{2}w+2zw^{2}+w^{3}$
$\displaystyle Z$ $=$ $\displaystyle y-z-w$

Modular covers

This modular curve minimally covers the modular curves listed below.

Covered curve Level Index Degree Genus Rank Kernel decomposition
36.72.0-18.a.1.12 $36$ $3$ $3$ $0$ $0$ full Jacobian

This modular curve is minimally covered by the modular curves in the database listed below.

Covering curve Level Index Degree Genus Rank Kernel decomposition
36.432.7-18.d.1.5 $36$ $2$ $2$ $7$ $0$ $1\cdot2^{2}$
36.432.7-36.f.1.6 $36$ $2$ $2$ $7$ $0$ $1\cdot2^{2}$
36.432.7-18.l.2.5 $36$ $2$ $2$ $7$ $0$ $1\cdot2^{2}$
36.432.7-36.t.1.4 $36$ $2$ $2$ $7$ $0$ $1\cdot2^{2}$
36.432.7-36.u.1.3 $36$ $2$ $2$ $7$ $0$ $1\cdot2^{2}$
36.432.7-36.bc.1.4 $36$ $2$ $2$ $7$ $0$ $1\cdot2^{2}$
36.432.7-36.bd.1.8 $36$ $2$ $2$ $7$ $0$ $1\cdot2^{2}$
36.432.7-36.be.1.6 $36$ $2$ $2$ $7$ $0$ $1\cdot2^{2}$
36.432.11-36.cu.1.3 $36$ $2$ $2$ $11$ $0$ $1^{3}\cdot2\cdot4$
36.432.11-36.cv.1.1 $36$ $2$ $2$ $11$ $0$ $1^{3}\cdot2\cdot4$
36.432.11-36.cw.1.7 $36$ $2$ $2$ $11$ $0$ $1^{3}\cdot2\cdot4$
36.432.11-36.cx.1.9 $36$ $2$ $2$ $11$ $0$ $1^{3}\cdot2\cdot4$
36.648.10-18.a.2.11 $36$ $3$ $3$ $10$ $0$ $1^{4}\cdot2^{2}$
72.432.7-72.j.1.6 $72$ $2$ $2$ $7$ $?$ not computed
72.432.7-72.w.1.6 $72$ $2$ $2$ $7$ $?$ not computed
72.432.7-72.ce.1.6 $72$ $2$ $2$ $7$ $?$ not computed
72.432.7-72.cf.1.7 $72$ $2$ $2$ $7$ $?$ not computed
72.432.7-72.cq.1.6 $72$ $2$ $2$ $7$ $?$ not computed
72.432.7-72.cr.1.6 $72$ $2$ $2$ $7$ $?$ not computed
72.432.7-72.cs.1.10 $72$ $2$ $2$ $7$ $?$ not computed
72.432.7-72.ct.1.13 $72$ $2$ $2$ $7$ $?$ not computed
72.432.11-72.ik.1.7 $72$ $2$ $2$ $11$ $?$ not computed
72.432.11-72.il.1.7 $72$ $2$ $2$ $11$ $?$ not computed
72.432.11-72.im.1.13 $72$ $2$ $2$ $11$ $?$ not computed
72.432.11-72.in.1.13 $72$ $2$ $2$ $11$ $?$ not computed
180.432.7-90.m.1.6 $180$ $2$ $2$ $7$ $?$ not computed
180.432.7-90.n.2.3 $180$ $2$ $2$ $7$ $?$ not computed
180.432.7-180.cm.1.12 $180$ $2$ $2$ $7$ $?$ not computed
180.432.7-180.cn.1.11 $180$ $2$ $2$ $7$ $?$ not computed
180.432.7-180.co.1.9 $180$ $2$ $2$ $7$ $?$ not computed
180.432.7-180.cp.1.12 $180$ $2$ $2$ $7$ $?$ not computed
180.432.7-180.cq.1.15 $180$ $2$ $2$ $7$ $?$ not computed
180.432.7-180.cr.1.13 $180$ $2$ $2$ $7$ $?$ not computed
180.432.11-180.fe.1.4 $180$ $2$ $2$ $11$ $?$ not computed
180.432.11-180.ff.1.3 $180$ $2$ $2$ $11$ $?$ not computed
180.432.11-180.fg.1.8 $180$ $2$ $2$ $11$ $?$ not computed
180.432.11-180.fh.1.7 $180$ $2$ $2$ $11$ $?$ not computed
252.432.7-126.da.1.2 $252$ $2$ $2$ $7$ $?$ not computed
252.432.7-126.db.1.1 $252$ $2$ $2$ $7$ $?$ not computed
252.432.7-252.fa.1.2 $252$ $2$ $2$ $7$ $?$ not computed
252.432.7-252.fb.1.11 $252$ $2$ $2$ $7$ $?$ not computed
252.432.7-252.fc.1.11 $252$ $2$ $2$ $7$ $?$ not computed
252.432.7-252.fd.1.4 $252$ $2$ $2$ $7$ $?$ not computed
252.432.7-252.fe.1.12 $252$ $2$ $2$ $7$ $?$ not computed
252.432.7-252.ff.1.12 $252$ $2$ $2$ $7$ $?$ not computed
252.432.11-252.ga.1.13 $252$ $2$ $2$ $11$ $?$ not computed
252.432.11-252.gb.1.13 $252$ $2$ $2$ $11$ $?$ not computed
252.432.11-252.gc.1.14 $252$ $2$ $2$ $11$ $?$ not computed
252.432.11-252.gd.1.14 $252$ $2$ $2$ $11$ $?$ not computed