Newspace parameters
comment: Compute space of new eigenforms
[N,k,chi] = [2156,2,Mod(1,2156)]
mf = mfinit([N,k,chi],0)
lf = mfeigenbasis(mf)
from sage.modular.dirichlet import DirichletCharacter
H = DirichletGroup(2156, base_ring=CyclotomicField(2))
chi = DirichletCharacter(H, H._module([0, 0, 0]))
N = Newforms(chi, 2, names="a")
//Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code
chi := DirichletCharacter("2156.1");
S:= CuspForms(chi, 2);
N := Newforms(S);
| Level: | \( N \) | \(=\) | \( 2156 = 2^{2} \cdot 7^{2} \cdot 11 \) |
| Weight: | \( k \) | \(=\) | \( 2 \) |
| Character orbit: | \([\chi]\) | \(=\) | 2156.a (trivial) |
Newform invariants
comment: select newform
sage: f = N[0] # Warning: the index may be different
gp: f = lf[1] \\ Warning: the index may be different
| Self dual: | yes |
| Analytic conductor: | \(17.2157466758\) |
| Analytic rank: | \(0\) |
| Dimension: | \(4\) |
| Coefficient field: | 4.4.301088.1 |
|
comment: defining polynomial
gp: f.mod \\ as an extension of the character field
|
|
| Defining polynomial: |
\( x^{4} - 13x^{2} + 18 \)
|
| Coefficient ring: | \(\Z[a_1, \ldots, a_{5}]\) |
| Coefficient ring index: | \( 1 \) |
| Twist minimal: | yes |
| Fricke sign: | \(-1\) |
| Sato-Tate group: | $\mathrm{SU}(2)$ |
$q$-expansion
comment: q-expansion
sage: f.q_expansion() # note that sage often uses an isomorphic number field
gp: mfcoefs(f, 20)
Coefficients of the \(q\)-expansion are expressed in terms of a basis \(1,\beta_1,\beta_2,\beta_3\) for the coefficient ring described below. We also show the integral \(q\)-expansion of the trace form.
Basis of coefficient ring in terms of a root \(\nu\) of
\( x^{4} - 13x^{2} + 18 \)
:
| \(\beta_{1}\) | \(=\) |
\( \nu \)
|
| \(\beta_{2}\) | \(=\) |
\( ( \nu^{3} - 10\nu ) / 3 \)
|
| \(\beta_{3}\) | \(=\) |
\( \nu^{2} - 7 \)
|
| \(\nu\) | \(=\) |
\( \beta_1 \)
|
| \(\nu^{2}\) | \(=\) |
\( \beta_{3} + 7 \)
|
| \(\nu^{3}\) | \(=\) |
\( 3\beta_{2} + 10\beta_1 \)
|
Embeddings
For each embedding \(\iota_m\) of the coefficient field, the values \(\iota_m(a_n)\) are shown below.
For more information on an embedded modular form you can click on its label.
comment: embeddings in the coefficient field
gp: mfembed(f)
| Label | \(\iota_m(\nu)\) | \( a_{2} \) | \( a_{3} \) | \( a_{4} \) | \( a_{5} \) | \( a_{6} \) | \( a_{7} \) | \( a_{8} \) | \( a_{9} \) | \( a_{10} \) | ||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 1.1 |
|
0 | −3.38000 | 0 | −1.60486 | 0 | 0 | 0 | 8.42443 | 0 | ||||||||||||||||||||||||||||||
| 1.2 | 0 | −1.25522 | 0 | 3.52483 | 0 | 0 | 0 | −1.42443 | 0 | |||||||||||||||||||||||||||||||
| 1.3 | 0 | 1.25522 | 0 | −3.52483 | 0 | 0 | 0 | −1.42443 | 0 | |||||||||||||||||||||||||||||||
| 1.4 | 0 | 3.38000 | 0 | 1.60486 | 0 | 0 | 0 | 8.42443 | 0 | |||||||||||||||||||||||||||||||
Atkin-Lehner signs
| \( p \) | Sign |
|---|---|
| \(2\) | \( -1 \) |
| \(7\) | \( -1 \) |
| \(11\) | \( -1 \) |
Inner twists
| Char | Parity | Ord | Mult | Type |
|---|---|---|---|---|
| 1.a | even | 1 | 1 | trivial |
| 7.b | odd | 2 | 1 | inner |
Twists
| By twisting character orbit | |||||||
|---|---|---|---|---|---|---|---|
| Char | Parity | Ord | Mult | Type | Twist | Min | Dim |
| 1.a | even | 1 | 1 | trivial | 2156.2.a.m | ✓ | 4 |
| 4.b | odd | 2 | 1 | 8624.2.a.cx | 4 | ||
| 7.b | odd | 2 | 1 | inner | 2156.2.a.m | ✓ | 4 |
| 7.c | even | 3 | 2 | 2156.2.i.n | 8 | ||
| 7.d | odd | 6 | 2 | 2156.2.i.n | 8 | ||
| 28.d | even | 2 | 1 | 8624.2.a.cx | 4 | ||
| By twisted newform orbit | |||||||
|---|---|---|---|---|---|---|---|
| Twist | Min | Dim | Char | Parity | Ord | Mult | Type |
| 2156.2.a.m | ✓ | 4 | 1.a | even | 1 | 1 | trivial |
| 2156.2.a.m | ✓ | 4 | 7.b | odd | 2 | 1 | inner |
| 2156.2.i.n | 8 | 7.c | even | 3 | 2 | ||
| 2156.2.i.n | 8 | 7.d | odd | 6 | 2 | ||
| 8624.2.a.cx | 4 | 4.b | odd | 2 | 1 | ||
| 8624.2.a.cx | 4 | 28.d | even | 2 | 1 | ||
Hecke kernels
This newform subspace can be constructed as the kernel of the linear operator
\( T_{3}^{4} - 13T_{3}^{2} + 18 \)
acting on \(S_{2}^{\mathrm{new}}(\Gamma_0(2156))\).
Hecke characteristic polynomials
| $p$ | $F_p(T)$ |
|---|---|
| $2$ |
\( T^{4} \)
|
| $3$ |
\( T^{4} - 13T^{2} + 18 \)
|
| $5$ |
\( T^{4} - 15T^{2} + 32 \)
|
| $7$ |
\( T^{4} \)
|
| $11$ |
\( (T - 1)^{4} \)
|
| $13$ |
\( T^{4} - 30T^{2} + 128 \)
|
| $17$ |
\( T^{4} - 26T^{2} + 72 \)
|
| $19$ |
\( T^{4} - 52T^{2} + 288 \)
|
| $23$ |
\( (T^{2} - 7 T - 12)^{2} \)
|
| $29$ |
\( (T + 6)^{4} \)
|
| $31$ |
\( T^{4} - 13T^{2} + 18 \)
|
| $37$ |
\( (T^{2} + T - 24)^{2} \)
|
| $41$ |
\( T^{4} - 154T^{2} + 5832 \)
|
| $43$ |
\( (T^{2} - 2 T - 96)^{2} \)
|
| $47$ |
\( T^{4} - 26T^{2} + 72 \)
|
| $53$ |
\( (T^{2} + 2 T - 96)^{2} \)
|
| $59$ |
\( T^{4} - 69T^{2} + 2 \)
|
| $61$ |
\( T^{4} - 138T^{2} + 8 \)
|
| $67$ |
\( (T^{2} - 17 T + 48)^{2} \)
|
| $71$ |
\( (T^{2} - T - 24)^{2} \)
|
| $73$ |
\( T^{4} - 234T^{2} + 5832 \)
|
| $79$ |
\( (T - 6)^{4} \)
|
| $83$ |
\( T^{4} - 104T^{2} + 1152 \)
|
| $89$ |
\( T^{4} - 215 T^{2} + 10368 \)
|
| $97$ |
\( T^{4} - 71T^{2} + 72 \)
|
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