Newspace parameters
comment: Compute space of new eigenforms
[N,k,chi] = [261,2,Mod(1,261)]
mf = mfinit([N,k,chi],0)
lf = mfeigenbasis(mf)
from sage.modular.dirichlet import DirichletCharacter
H = DirichletGroup(261, base_ring=CyclotomicField(2))
chi = DirichletCharacter(H, H._module([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("261.1");
S:= CuspForms(chi, 2);
N := Newforms(S);
| Level: | \( N \) | \(=\) | \( 261 = 3^{2} \cdot 29 \) |
| Weight: | \( k \) | \(=\) | \( 2 \) |
| Character orbit: | \([\chi]\) | \(=\) | 261.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: | \(2.08409549276\) |
| Analytic rank: | \(1\) |
| Dimension: | \(2\) |
| Coefficient field: | \(\Q(\sqrt{5}) \) |
|
comment: defining polynomial
gp: f.mod \\ as an extension of the character field
|
|
| Defining polynomial: |
\( x^{2} - x - 1 \)
|
| Coefficient ring: | \(\Z[a_1, a_2]\) |
| Coefficient ring index: | \( 1 \) |
| Twist minimal: | no (minimal twist has level 87) |
| 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 \(\beta = \frac{1}{2}(1 + \sqrt{5})\). We also show the integral \(q\)-expansion of the trace form.
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 |
|
−1.61803 | 0 | 0.618034 | 1.23607 | 0 | −4.23607 | 2.23607 | 0 | −2.00000 | ||||||||||||||||||||||||
| 1.2 | 0.618034 | 0 | −1.61803 | −3.23607 | 0 | 0.236068 | −2.23607 | 0 | −2.00000 | |||||||||||||||||||||||||
Atkin-Lehner signs
| \( p \) | Sign |
|---|---|
| \(3\) | \(-1\) |
| \(29\) | \(-1\) |
Inner twists
This newform does not admit any (nontrivial) inner twists.
Twists
| By twisting character orbit | |||||||
|---|---|---|---|---|---|---|---|
| Char | Parity | Ord | Mult | Type | Twist | Min | Dim |
| 1.a | even | 1 | 1 | trivial | 261.2.a.b | 2 | |
| 3.b | odd | 2 | 1 | 87.2.a.a | ✓ | 2 | |
| 4.b | odd | 2 | 1 | 4176.2.a.bn | 2 | ||
| 5.b | even | 2 | 1 | 6525.2.a.ba | 2 | ||
| 12.b | even | 2 | 1 | 1392.2.a.q | 2 | ||
| 15.d | odd | 2 | 1 | 2175.2.a.l | 2 | ||
| 15.e | even | 4 | 2 | 2175.2.c.k | 4 | ||
| 21.c | even | 2 | 1 | 4263.2.a.j | 2 | ||
| 24.f | even | 2 | 1 | 5568.2.a.bs | 2 | ||
| 24.h | odd | 2 | 1 | 5568.2.a.bl | 2 | ||
| 29.b | even | 2 | 1 | 7569.2.a.k | 2 | ||
| 87.d | odd | 2 | 1 | 2523.2.a.c | 2 | ||
| By twisted newform orbit | |||||||
|---|---|---|---|---|---|---|---|
| Twist | Min | Dim | Char | Parity | Ord | Mult | Type |
| 87.2.a.a | ✓ | 2 | 3.b | odd | 2 | 1 | |
| 261.2.a.b | 2 | 1.a | even | 1 | 1 | trivial | |
| 1392.2.a.q | 2 | 12.b | even | 2 | 1 | ||
| 2175.2.a.l | 2 | 15.d | odd | 2 | 1 | ||
| 2175.2.c.k | 4 | 15.e | even | 4 | 2 | ||
| 2523.2.a.c | 2 | 87.d | odd | 2 | 1 | ||
| 4176.2.a.bn | 2 | 4.b | odd | 2 | 1 | ||
| 4263.2.a.j | 2 | 21.c | even | 2 | 1 | ||
| 5568.2.a.bl | 2 | 24.h | odd | 2 | 1 | ||
| 5568.2.a.bs | 2 | 24.f | even | 2 | 1 | ||
| 6525.2.a.ba | 2 | 5.b | even | 2 | 1 | ||
| 7569.2.a.k | 2 | 29.b | even | 2 | 1 | ||
Hecke kernels
This newform subspace can be constructed as the intersection of the kernels of the following linear operators acting on \(S_{2}^{\mathrm{new}}(\Gamma_0(261))\):
|
\( T_{2}^{2} + T_{2} - 1 \)
|
|
\( T_{5}^{2} + 2T_{5} - 4 \)
|
Hecke characteristic polynomials
| $p$ | $F_p(T)$ |
|---|---|
| $2$ |
\( T^{2} + T - 1 \)
|
| $3$ |
\( T^{2} \)
|
| $5$ |
\( T^{2} + 2T - 4 \)
|
| $7$ |
\( T^{2} + 4T - 1 \)
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| $11$ |
\( T^{2} + 4T - 1 \)
|
| $13$ |
\( T^{2} + 2T - 19 \)
|
| $17$ |
\( (T + 3)^{2} \)
|
| $19$ |
\( T^{2} + 10T + 20 \)
|
| $23$ |
\( T^{2} - 2T - 44 \)
|
| $29$ |
\( (T - 1)^{2} \)
|
| $31$ |
\( T^{2} + 6T - 36 \)
|
| $37$ |
\( T^{2} - 6T + 4 \)
|
| $41$ |
\( (T + 2)^{2} \)
|
| $43$ |
\( (T - 4)^{2} \)
|
| $47$ |
\( T^{2} - 4T - 41 \)
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| $53$ |
\( T^{2} + 18T + 76 \)
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| $59$ |
\( T^{2} - 20 \)
|
| $61$ |
\( T^{2} + 6T + 4 \)
|
| $67$ |
\( T^{2} + 4T - 121 \)
|
| $71$ |
\( T^{2} - 6T + 4 \)
|
| $73$ |
\( T^{2} - 18T + 76 \)
|
| $79$ |
\( T^{2} + 30T + 220 \)
|
| $83$ |
\( T^{2} - 12T - 44 \)
|
| $89$ |
\( (T + 5)^{2} \)
|
| $97$ |
\( T^{2} - 6T - 236 \)
|
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