Properties

Label 256.8.b.d
Level $256$
Weight $8$
Character orbit 256.b
Analytic conductor $79.971$
Analytic rank $0$
Dimension $2$
CM discriminant -4
Inner twists $4$

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Show commands: Magma / PariGP / SageMath

Newspace parameters

comment: Compute space of new eigenforms
 
[N,k,chi] = [256,8,Mod(129,256)]
 
mf = mfinit([N,k,chi],0)
 
lf = mfeigenbasis(mf)
 
from sage.modular.dirichlet import DirichletCharacter
 
H = DirichletGroup(256, base_ring=CyclotomicField(2))
 
chi = DirichletCharacter(H, H._module([0, 1]))
 
N = Newforms(chi, 8, names="a")
 
//Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code
 
chi := DirichletCharacter("256.129");
 
S:= CuspForms(chi, 8);
 
N := Newforms(S);
 
Level: \( N \) \(=\) \( 256 = 2^{8} \)
Weight: \( k \) \(=\) \( 8 \)
Character orbit: \([\chi]\) \(=\) 256.b (of order \(2\), degree \(1\), not 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: \(79.9705665239\)
Analytic rank: \(0\)
Dimension: \(2\)
Coefficient field: \(\Q(\sqrt{-1}) \)
comment: defining polynomial
 
gp: f.mod \\ as an extension of the character field
 
Defining polynomial: \( x^{2} + 1 \) Copy content Toggle raw display
Coefficient ring: \(\Z[a_1, \ldots, a_{13}]\)
Coefficient ring index: \( 2 \)
Twist minimal: no (minimal twist has level 32)
Sato-Tate group: $\mathrm{U}(1)[D_{2}]$

$q$-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 \(\beta = 2i\). We also show the integral \(q\)-expansion of the trace form.

\(f(q)\) \(=\) \( q + 29 \beta q^{5} + 2187 q^{9} - 4449 \beta q^{13} - 40094 q^{17} + 74761 q^{25} + 116615 \beta q^{29} - 281987 \beta q^{37} - 9530 q^{41} + 63423 \beta q^{45} - 823543 q^{49} + 399301 \beta q^{53} - 1752665 \beta q^{61} + \cdots - 17567406 q^{97} +O(q^{100}) \) Copy content Toggle raw display
\(\operatorname{Tr}(f)(q)\) \(=\) \( 2 q + 4374 q^{9} - 80188 q^{17} + 149522 q^{25} - 19060 q^{41} - 1647086 q^{49} + 1032168 q^{65} - 7834836 q^{73} + 9565938 q^{81} - 18492340 q^{89} - 35134812 q^{97}+O(q^{100}) \) Copy content Toggle raw display

Character values

We give the values of \(\chi\) on generators for \(\left(\mathbb{Z}/256\mathbb{Z}\right)^\times\).

\(n\) \(5\) \(255\)
\(\chi(n)\) \(-1\) \(1\)

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   \(\iota_m(\nu)\) \( a_{2} \) \( a_{3} \) \( a_{4} \) \( a_{5} \) \( a_{6} \) \( a_{7} \) \( a_{8} \) \( a_{9} \) \( a_{10} \)
129.1
1.00000i
1.00000i
0 0 0 58.0000i 0 0 0 2187.00 0
129.2 0 0 0 58.0000i 0 0 0 2187.00 0
\(n\): e.g. 2-40 or 990-1000
Significant digits:
Format:

Inner twists

Char Parity Ord Mult Type
1.a even 1 1 trivial
4.b odd 2 1 CM by \(\Q(\sqrt{-1}) \)
8.b even 2 1 inner
8.d odd 2 1 inner

Twists

       By twisting character orbit
Char Parity Ord Mult Type Twist Min Dim
1.a even 1 1 trivial 256.8.b.d 2
4.b odd 2 1 CM 256.8.b.d 2
8.b even 2 1 inner 256.8.b.d 2
8.d odd 2 1 inner 256.8.b.d 2
16.e even 4 1 32.8.a.a 1
16.e even 4 1 64.8.a.d 1
16.f odd 4 1 32.8.a.a 1
16.f odd 4 1 64.8.a.d 1
48.i odd 4 1 288.8.a.b 1
48.i odd 4 1 576.8.a.n 1
48.k even 4 1 288.8.a.b 1
48.k even 4 1 576.8.a.n 1
    
        By twisted newform orbit
Twist Min Dim Char Parity Ord Mult Type
32.8.a.a 1 16.e even 4 1
32.8.a.a 1 16.f odd 4 1
64.8.a.d 1 16.e even 4 1
64.8.a.d 1 16.f odd 4 1
256.8.b.d 2 1.a even 1 1 trivial
256.8.b.d 2 4.b odd 2 1 CM
256.8.b.d 2 8.b even 2 1 inner
256.8.b.d 2 8.d odd 2 1 inner
288.8.a.b 1 48.i odd 4 1
288.8.a.b 1 48.k even 4 1
576.8.a.n 1 48.i odd 4 1
576.8.a.n 1 48.k even 4 1

Hecke kernels

This newform subspace can be constructed as the intersection of the kernels of the following linear operators acting on \(S_{8}^{\mathrm{new}}(256, [\chi])\):

\( T_{3} \) Copy content Toggle raw display
\( T_{7} \) Copy content Toggle raw display

Hecke characteristic polynomials

$p$ $F_p(T)$
$2$ \( T^{2} \) Copy content Toggle raw display
$3$ \( T^{2} \) Copy content Toggle raw display
$5$ \( T^{2} + 3364 \) Copy content Toggle raw display
$7$ \( T^{2} \) Copy content Toggle raw display
$11$ \( T^{2} \) Copy content Toggle raw display
$13$ \( T^{2} + 79174404 \) Copy content Toggle raw display
$17$ \( (T + 40094)^{2} \) Copy content Toggle raw display
$19$ \( T^{2} \) Copy content Toggle raw display
$23$ \( T^{2} \) Copy content Toggle raw display
$29$ \( T^{2} + 54396232900 \) Copy content Toggle raw display
$31$ \( T^{2} \) Copy content Toggle raw display
$37$ \( T^{2} + 318066672676 \) Copy content Toggle raw display
$41$ \( (T + 9530)^{2} \) Copy content Toggle raw display
$43$ \( T^{2} \) Copy content Toggle raw display
$47$ \( T^{2} \) Copy content Toggle raw display
$53$ \( T^{2} + 637765154404 \) Copy content Toggle raw display
$59$ \( T^{2} \) Copy content Toggle raw display
$61$ \( T^{2} + 12287338408900 \) Copy content Toggle raw display
$67$ \( T^{2} \) Copy content Toggle raw display
$71$ \( T^{2} \) Copy content Toggle raw display
$73$ \( (T + 3917418)^{2} \) Copy content Toggle raw display
$79$ \( T^{2} \) Copy content Toggle raw display
$83$ \( T^{2} \) Copy content Toggle raw display
$89$ \( (T + 9246170)^{2} \) Copy content Toggle raw display
$97$ \( (T + 17567406)^{2} \) Copy content Toggle raw display
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