Invariants
| Level: | $40$ | $\SL_2$-level: | $4$ | ||||
| Index: | $24$ | $\PSL_2$-index: | $12$ | ||||
| Genus: | $0 = 1 + \frac{ 12 }{12} - \frac{ 0 }{4} - \frac{ 0 }{3} - \frac{ 4 }{2}$ | ||||||
| Cusps: | $4$ (of which $2$ are rational) | Cusp widths | $2^{2}\cdot4^{2}$ | Cusp orbits | $1^{2}\cdot2$ | ||
| Elliptic points: | $0$ of order $2$ and $0$ of order $3$ | ||||||
| $\Q$-gonality: | $1$ | ||||||
| $\overline{\Q}$-gonality: | $1$ | ||||||
| Rational cusps: | $2$ | ||||||
| Rational CM points: | none |
Other labels
| Cummins and Pauli (CP) label: | 4E0 |
| Rouse, Sutherland, and Zureick-Brown (RSZB) label: | 40.24.0.128 |
Level structure
| $\GL_2(\Z/40\Z)$-generators: | $\begin{bmatrix}7&36\\4&29\end{bmatrix}$, $\begin{bmatrix}11&16\\4&11\end{bmatrix}$, $\begin{bmatrix}11&34\\20&37\end{bmatrix}$, $\begin{bmatrix}17&14\\34&27\end{bmatrix}$ |
| Contains $-I$: | no $\quad$ (see 8.12.0.b.1 for the level structure with $-I$) |
| Cyclic 40-isogeny field degree: | $24$ |
| Cyclic 40-torsion field degree: | $384$ |
| Full 40-torsion field degree: | $30720$ |
Models
This modular curve is isomorphic to $\mathbb{P}^1$.
Rational points
This modular curve has infinitely many rational points, including 624 stored non-cuspidal points.
Maps to other modular curves
$j$-invariant map of degree 12 to the modular curve $X(1)$ :
| $\displaystyle j$ | $=$ | $\displaystyle 2^2\,\frac{x^{12}(64x^{4}+8x^{2}y^{2}+y^{4})^{3}}{y^{4}x^{16}(8x^{2}+y^{2})^{2}}$ |
Modular covers
This modular curve minimally covers the modular curves listed below.
| Covered curve | Level | Index | Degree | Genus | Rank |
|---|---|---|---|---|---|
| 20.12.0-2.a.1.2 | $20$ | $2$ | $2$ | $0$ | $0$ |
| 40.12.0-2.a.1.1 | $40$ | $2$ | $2$ | $0$ | $0$ |
This modular curve is minimally covered by the modular curves in the database listed below.
| Covering curve | Level | Index | Degree | Genus |
|---|---|---|---|---|
| 40.48.0-8.b.1.3 | $40$ | $2$ | $2$ | $0$ |
| 40.48.0-8.c.1.5 | $40$ | $2$ | $2$ | $0$ |
| 40.48.0-8.c.1.10 | $40$ | $2$ | $2$ | $0$ |
| 120.48.0-24.f.1.6 | $120$ | $2$ | $2$ | $0$ |
| 120.48.0-24.f.1.7 | $120$ | $2$ | $2$ | $0$ |
| 120.48.0-24.g.1.6 | $120$ | $2$ | $2$ | $0$ |
| 120.48.0-24.g.1.8 | $120$ | $2$ | $2$ | $0$ |
| 120.72.2-24.b.1.7 | $120$ | $3$ | $3$ | $2$ |
| 120.96.1-24.bx.1.17 | $120$ | $4$ | $4$ | $1$ |
| 40.48.0-40.f.1.3 | $40$ | $2$ | $2$ | $0$ |
| 40.48.0-40.f.1.5 | $40$ | $2$ | $2$ | $0$ |
| 40.48.0-40.g.1.1 | $40$ | $2$ | $2$ | $0$ |
| 40.48.0-40.g.1.5 | $40$ | $2$ | $2$ | $0$ |
| 40.120.4-40.b.1.3 | $40$ | $5$ | $5$ | $4$ |
| 40.144.3-40.b.1.9 | $40$ | $6$ | $6$ | $3$ |
| 40.240.7-40.b.1.10 | $40$ | $10$ | $10$ | $7$ |
| 280.48.0-56.f.1.6 | $280$ | $2$ | $2$ | $0$ |
| 280.48.0-56.f.1.7 | $280$ | $2$ | $2$ | $0$ |
| 280.48.0-56.g.1.4 | $280$ | $2$ | $2$ | $0$ |
| 280.48.0-56.g.1.8 | $280$ | $2$ | $2$ | $0$ |
| 280.192.5-56.b.1.18 | $280$ | $8$ | $8$ | $5$ |
| 280.504.16-56.b.1.15 | $280$ | $21$ | $21$ | $16$ |
| 120.48.0-120.f.1.6 | $120$ | $2$ | $2$ | $0$ |
| 120.48.0-120.f.1.12 | $120$ | $2$ | $2$ | $0$ |
| 120.48.0-120.g.1.8 | $120$ | $2$ | $2$ | $0$ |
| 120.48.0-120.g.1.11 | $120$ | $2$ | $2$ | $0$ |
| 280.48.0-280.f.1.4 | $280$ | $2$ | $2$ | $0$ |
| 280.48.0-280.f.1.14 | $280$ | $2$ | $2$ | $0$ |
| 280.48.0-280.g.1.7 | $280$ | $2$ | $2$ | $0$ |
| 280.48.0-280.g.1.14 | $280$ | $2$ | $2$ | $0$ |