Newspace parameters
comment: Compute space of new eigenforms
[N,k,chi] = [84,2,Mod(55,84)]
mf = mfinit([N,k,chi],0)
lf = mfeigenbasis(mf)
from sage.modular.dirichlet import DirichletCharacter
H = DirichletGroup(84, base_ring=CyclotomicField(2))
chi = DirichletCharacter(H, H._module([1, 0, 1]))
N = Newforms(chi, 2, names="a")
//Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code
chi := DirichletCharacter("84.55");
S:= CuspForms(chi, 2);
N := Newforms(S);
| Level: | \( N \) | \(=\) | \( 84 = 2^{2} \cdot 3 \cdot 7 \) |
| Weight: | \( k \) | \(=\) | \( 2 \) |
| Character orbit: | \([\chi]\) | \(=\) | 84.b (of order \(2\), degree \(1\), minimal) |
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: | no |
| Analytic conductor: | \(0.670743376979\) |
| Analytic rank: | \(0\) |
| Dimension: | \(4\) |
| Coefficient field: | 4.0.2312.1 |
|
comment: defining polynomial
gp: f.mod \\ as an extension of the character field
|
|
| Defining polynomial: |
\( x^{4} - x^{3} - 2x + 4 \)
|
| Coefficient ring: | \(\Z[a_1, a_2]\) |
| Coefficient ring index: | \( 2 \) |
| Twist minimal: | yes |
| Sato-Tate group: | $\mathrm{SU}(2)[C_{2}]$ |
$q$-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
\( x^{4} - x^{3} - 2x + 4 \)
:
| \(\beta_{1}\) | \(=\) |
\( \nu \)
|
| \(\beta_{2}\) | \(=\) |
\( \nu^{2} \)
|
| \(\beta_{3}\) | \(=\) |
\( \nu^{3} - 2 \)
|
| \(\nu\) | \(=\) |
\( \beta_1 \)
|
| \(\nu^{2}\) | \(=\) |
\( \beta_{2} \)
|
| \(\nu^{3}\) | \(=\) |
\( \beta_{3} + 2 \)
|
Character values
We give the values of \(\chi\) on generators for \(\left(\mathbb{Z}/84\mathbb{Z}\right)^\times\).
| \(n\) | \(29\) | \(43\) | \(73\) |
| \(\chi(n)\) | \(1\) | \(-1\) | \(-1\) |
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 | \(\iota_m(\nu)\) | \( a_{2} \) | \( a_{3} \) | \( a_{4} \) | \( a_{5} \) | \( a_{6} \) | \( a_{7} \) | \( a_{8} \) | \( a_{9} \) | \( a_{10} \) | ||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 55.1 |
|
−1.28078 | − | 0.599676i | 1.00000 | 1.28078 | + | 1.53610i | 3.33513i | −1.28078 | − | 0.599676i | 1.56155 | − | 2.13578i | −0.719224 | − | 2.73546i | 1.00000 | 2.00000 | − | 4.27156i | ||||||||||||||||||
| 55.2 | −1.28078 | + | 0.599676i | 1.00000 | 1.28078 | − | 1.53610i | − | 3.33513i | −1.28078 | + | 0.599676i | 1.56155 | + | 2.13578i | −0.719224 | + | 2.73546i | 1.00000 | 2.00000 | + | 4.27156i | ||||||||||||||||||
| 55.3 | 0.780776 | − | 1.17915i | 1.00000 | −0.780776 | − | 1.84130i | 1.69614i | 0.780776 | − | 1.17915i | −2.56155 | + | 0.662153i | −2.78078 | − | 0.516994i | 1.00000 | 2.00000 | + | 1.32431i | |||||||||||||||||||
| 55.4 | 0.780776 | + | 1.17915i | 1.00000 | −0.780776 | + | 1.84130i | − | 1.69614i | 0.780776 | + | 1.17915i | −2.56155 | − | 0.662153i | −2.78078 | + | 0.516994i | 1.00000 | 2.00000 | − | 1.32431i | ||||||||||||||||||
Inner twists
| Char | Parity | Ord | Mult | Type |
|---|---|---|---|---|
| 1.a | even | 1 | 1 | trivial |
| 28.d | even | 2 | 1 | inner |
Twists
| By twisting character orbit | |||||||
|---|---|---|---|---|---|---|---|
| Char | Parity | Ord | Mult | Type | Twist | Min | Dim |
| 1.a | even | 1 | 1 | trivial | 84.2.b.b | yes | 4 |
| 3.b | odd | 2 | 1 | 252.2.b.d | 4 | ||
| 4.b | odd | 2 | 1 | 84.2.b.a | ✓ | 4 | |
| 7.b | odd | 2 | 1 | 84.2.b.a | ✓ | 4 | |
| 7.c | even | 3 | 2 | 588.2.o.a | 8 | ||
| 7.d | odd | 6 | 2 | 588.2.o.c | 8 | ||
| 8.b | even | 2 | 1 | 1344.2.b.e | 4 | ||
| 8.d | odd | 2 | 1 | 1344.2.b.f | 4 | ||
| 12.b | even | 2 | 1 | 252.2.b.e | 4 | ||
| 21.c | even | 2 | 1 | 252.2.b.e | 4 | ||
| 24.f | even | 2 | 1 | 4032.2.b.n | 4 | ||
| 24.h | odd | 2 | 1 | 4032.2.b.j | 4 | ||
| 28.d | even | 2 | 1 | inner | 84.2.b.b | yes | 4 |
| 28.f | even | 6 | 2 | 588.2.o.a | 8 | ||
| 28.g | odd | 6 | 2 | 588.2.o.c | 8 | ||
| 56.e | even | 2 | 1 | 1344.2.b.e | 4 | ||
| 56.h | odd | 2 | 1 | 1344.2.b.f | 4 | ||
| 84.h | odd | 2 | 1 | 252.2.b.d | 4 | ||
| 168.e | odd | 2 | 1 | 4032.2.b.j | 4 | ||
| 168.i | even | 2 | 1 | 4032.2.b.n | 4 | ||
| By twisted newform orbit | |||||||
|---|---|---|---|---|---|---|---|
| Twist | Min | Dim | Char | Parity | Ord | Mult | Type |
| 84.2.b.a | ✓ | 4 | 4.b | odd | 2 | 1 | |
| 84.2.b.a | ✓ | 4 | 7.b | odd | 2 | 1 | |
| 84.2.b.b | yes | 4 | 1.a | even | 1 | 1 | trivial |
| 84.2.b.b | yes | 4 | 28.d | even | 2 | 1 | inner |
| 252.2.b.d | 4 | 3.b | odd | 2 | 1 | ||
| 252.2.b.d | 4 | 84.h | odd | 2 | 1 | ||
| 252.2.b.e | 4 | 12.b | even | 2 | 1 | ||
| 252.2.b.e | 4 | 21.c | even | 2 | 1 | ||
| 588.2.o.a | 8 | 7.c | even | 3 | 2 | ||
| 588.2.o.a | 8 | 28.f | even | 6 | 2 | ||
| 588.2.o.c | 8 | 7.d | odd | 6 | 2 | ||
| 588.2.o.c | 8 | 28.g | odd | 6 | 2 | ||
| 1344.2.b.e | 4 | 8.b | even | 2 | 1 | ||
| 1344.2.b.e | 4 | 56.e | even | 2 | 1 | ||
| 1344.2.b.f | 4 | 8.d | odd | 2 | 1 | ||
| 1344.2.b.f | 4 | 56.h | odd | 2 | 1 | ||
| 4032.2.b.j | 4 | 24.h | odd | 2 | 1 | ||
| 4032.2.b.j | 4 | 168.e | odd | 2 | 1 | ||
| 4032.2.b.n | 4 | 24.f | even | 2 | 1 | ||
| 4032.2.b.n | 4 | 168.i | even | 2 | 1 | ||
Hecke kernels
This newform subspace can be constructed as the kernel of the linear operator
\( T_{19}^{2} + 6T_{19} - 8 \)
acting on \(S_{2}^{\mathrm{new}}(84, [\chi])\).
Hecke characteristic polynomials
| $p$ | $F_p(T)$ |
|---|---|
| $2$ |
\( T^{4} + T^{3} + 2T + 4 \)
|
| $3$ |
\( (T - 1)^{4} \)
|
| $5$ |
\( T^{4} + 14T^{2} + 32 \)
|
| $7$ |
\( T^{4} + 2 T^{3} + \cdots + 49 \)
|
| $11$ |
\( T^{4} + 10T^{2} + 8 \)
|
| $13$ |
\( T^{4} + 40T^{2} + 128 \)
|
| $17$ |
\( T^{4} + 46T^{2} + 512 \)
|
| $19$ |
\( (T^{2} + 6 T - 8)^{2} \)
|
| $23$ |
\( T^{4} + 10T^{2} + 8 \)
|
| $29$ |
\( (T + 2)^{4} \)
|
| $31$ |
\( T^{4} \)
|
| $37$ |
\( (T^{2} + 6 T - 8)^{2} \)
|
| $41$ |
\( T^{4} + 62T^{2} + 128 \)
|
| $43$ |
\( T^{4} + 148T^{2} + 5408 \)
|
| $47$ |
\( (T^{2} - 4 T - 64)^{2} \)
|
| $53$ |
\( (T^{2} - 8 T - 52)^{2} \)
|
| $59$ |
\( (T + 4)^{4} \)
|
| $61$ |
\( T^{4} + 112T^{2} + 2048 \)
|
| $67$ |
\( T^{4} + 124T^{2} + 512 \)
|
| $71$ |
\( T^{4} + 170T^{2} + 2312 \)
|
| $73$ |
\( T^{4} + 56T^{2} + 512 \)
|
| $79$ |
\( T^{4} + 28T^{2} + 128 \)
|
| $83$ |
\( (T^{2} - 4 T - 64)^{2} \)
|
| $89$ |
\( T^{4} + 62T^{2} + 128 \)
|
| $97$ |
\( T^{4} + 184T^{2} + 8192 \)
|
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