Properties

Label 820.2.bm.b
Level $820$
Weight $2$
Character orbit 820.bm
Analytic conductor $6.548$
Analytic rank $0$
Dimension $8$
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] = [820,2,Mod(23,820)]
 
mf = mfinit([N,k,chi],0)
 
lf = mfeigenbasis(mf)
 
from sage.modular.dirichlet import DirichletCharacter
 
H = DirichletGroup(820, base_ring=CyclotomicField(20))
 
chi = DirichletCharacter(H, H._module([10, 15, 18]))
 
N = Newforms(chi, 2, names="a")
 
//Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code
 
chi := DirichletCharacter("820.23");
 
S:= CuspForms(chi, 2);
 
N := Newforms(S);
 
Level: \( N \) \(=\) \( 820 = 2^{2} \cdot 5 \cdot 41 \)
Weight: \( k \) \(=\) \( 2 \)
Character orbit: \([\chi]\) \(=\) 820.bm (of order \(20\), degree \(8\), 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: \(6.54773296574\)
Analytic rank: \(0\)
Dimension: \(8\)
Coefficient field: \(\Q(\zeta_{20})\)
comment: defining polynomial
 
gp: f.mod \\ as an extension of the character field
 
Defining polynomial: \( x^{8} - x^{6} + x^{4} - x^{2} + 1 \) Copy content Toggle raw display
Coefficient ring: \(\Z[a_1, \ldots, a_{5}]\)
Coefficient ring index: \( 1 \)
Twist minimal: yes
Sato-Tate group: $\mathrm{U}(1)[D_{20}]$

$q$-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 primitive root of unity \(\zeta_{20}\). We also show the integral \(q\)-expansion of the trace form.

\(f(q)\) \(=\) \( q + (\zeta_{20}^{6} - \zeta_{20}) q^{2} - 2 \zeta_{20}^{7} q^{4} + (2 \zeta_{20}^{6} - 2 \zeta_{20}^{4} + \cdots - 2) q^{5} + \cdots + 3 \zeta_{20}^{5} q^{9} +O(q^{10}) \) Copy content Toggle raw display \( q + (\zeta_{20}^{6} - \zeta_{20}) q^{2} - 2 \zeta_{20}^{7} q^{4} + (2 \zeta_{20}^{6} - 2 \zeta_{20}^{4} + \cdots - 2) q^{5} + \cdots + (7 \zeta_{20}^{7} + \cdots - 7 \zeta_{20}) q^{98} +O(q^{100}) \) Copy content Toggle raw display
\(\operatorname{Tr}(f)(q)\) \(=\) \( 8 q + 2 q^{2} - 4 q^{5} - 4 q^{8}+O(q^{10}) \) Copy content Toggle raw display \( 8 q + 2 q^{2} - 4 q^{5} - 4 q^{8} + 6 q^{10} + 10 q^{13} + 8 q^{16} - 10 q^{17} - 6 q^{18} + 16 q^{20} - 6 q^{25} - 10 q^{26} - 20 q^{29} + 32 q^{32} - 30 q^{34} + 12 q^{36} - 4 q^{37} - 4 q^{40} + 8 q^{41} - 6 q^{45} + 14 q^{50} + 20 q^{52} + 10 q^{53} + 20 q^{58} - 24 q^{61} + 30 q^{65} - 20 q^{68} - 12 q^{72} - 22 q^{73} - 50 q^{74} + 16 q^{80} - 72 q^{81} + 2 q^{82} - 30 q^{85} + 20 q^{89} - 6 q^{90} - 50 q^{97} + 14 q^{98}+O(q^{100}) \) Copy content Toggle raw display

Character values

We give the values of \(\chi\) on generators for \(\left(\mathbb{Z}/820\mathbb{Z}\right)^\times\).

\(n\) \(411\) \(621\) \(657\)
\(\chi(n)\) \(-1\) \(\zeta_{20}^{2}\) \(\zeta_{20}^{5}\)

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   \(\iota_m(\nu)\) \( a_{2} \) \( a_{3} \) \( a_{4} \) \( a_{5} \) \( a_{6} \) \( a_{7} \) \( a_{8} \) \( a_{9} \) \( a_{10} \)
23.1
0.951057 0.309017i
0.951057 + 0.309017i
−0.587785 0.809017i
−0.951057 + 0.309017i
−0.587785 + 0.809017i
0.587785 0.809017i
−0.951057 0.309017i
0.587785 + 0.809017i
−1.26007 0.642040i 0 1.17557 + 1.61803i −1.03025 1.98459i 0 0 −0.442463 2.79360i 3.00000i 0.0240055 + 3.16219i
107.1 −1.26007 + 0.642040i 0 1.17557 1.61803i −1.03025 + 1.98459i 0 0 −0.442463 + 2.79360i 3.00000i 0.0240055 3.16219i
127.1 1.39680 + 0.221232i 0 1.90211 + 0.618034i 1.56909 + 1.59310i 0 0 2.52015 + 1.28408i 3.00000i 1.83927 + 2.57237i
187.1 0.642040 1.26007i 0 −1.17557 1.61803i −2.20582 0.366554i 0 0 −2.79360 + 0.442463i 3.00000i −1.87811 + 2.54415i
523.1 1.39680 0.221232i 0 1.90211 0.618034i 1.56909 1.59310i 0 0 2.52015 1.28408i 3.00000i 1.83927 2.57237i
687.1 0.221232 + 1.39680i 0 −1.90211 + 0.618034i −0.333023 2.21113i 0 0 −1.28408 2.52015i 3.00000i 3.01484 0.954339i
763.1 0.642040 + 1.26007i 0 −1.17557 + 1.61803i −2.20582 + 0.366554i 0 0 −2.79360 0.442463i 3.00000i −1.87811 2.54415i
783.1 0.221232 1.39680i 0 −1.90211 0.618034i −0.333023 + 2.21113i 0 0 −1.28408 + 2.52015i 3.00000i 3.01484 + 0.954339i
\(n\): e.g. 2-40 or 990-1000
Embeddings: e.g. 1-3 or 23.1
Significant digits:
Format:

Inner twists

Char Parity Ord Mult Type
1.a even 1 1 trivial
4.b odd 2 1 CM by \(\Q(\sqrt{-1}) \)
205.v odd 20 1 inner
820.bm even 20 1 inner

Twists

       By twisting character orbit
Char Parity Ord Mult Type Twist Min Dim
1.a even 1 1 trivial 820.2.bm.b yes 8
4.b odd 2 1 CM 820.2.bm.b yes 8
5.c odd 4 1 820.2.bm.a 8
20.e even 4 1 820.2.bm.a 8
41.f even 10 1 820.2.bm.a 8
164.l odd 10 1 820.2.bm.a 8
205.v odd 20 1 inner 820.2.bm.b yes 8
820.bm even 20 1 inner 820.2.bm.b yes 8
    
        By twisted newform orbit
Twist Min Dim Char Parity Ord Mult Type
820.2.bm.a 8 5.c odd 4 1
820.2.bm.a 8 20.e even 4 1
820.2.bm.a 8 41.f even 10 1
820.2.bm.a 8 164.l odd 10 1
820.2.bm.b yes 8 1.a even 1 1 trivial
820.2.bm.b yes 8 4.b odd 2 1 CM
820.2.bm.b yes 8 205.v odd 20 1 inner
820.2.bm.b yes 8 820.bm even 20 1 inner

Hecke kernels

This newform subspace can be constructed as the intersection of the kernels of the following linear operators acting on \(S_{2}^{\mathrm{new}}(820, [\chi])\):

\( T_{3} \) Copy content Toggle raw display
\( T_{13}^{8} - 10T_{13}^{7} + 50T_{13}^{6} - 260T_{13}^{5} + 1660T_{13}^{4} - 4550T_{13}^{3} + 17425T_{13}^{2} - 22800T_{13} + 9025 \) Copy content Toggle raw display

Hecke characteristic polynomials

$p$ $F_p(T)$
$2$ \( T^{8} - 2 T^{7} + \cdots + 16 \) Copy content Toggle raw display
$3$ \( T^{8} \) Copy content Toggle raw display
$5$ \( T^{8} + 4 T^{7} + \cdots + 625 \) Copy content Toggle raw display
$7$ \( T^{8} \) Copy content Toggle raw display
$11$ \( T^{8} \) Copy content Toggle raw display
$13$ \( T^{8} - 10 T^{7} + \cdots + 9025 \) Copy content Toggle raw display
$17$ \( T^{8} + 10 T^{7} + \cdots + 93025 \) Copy content Toggle raw display
$19$ \( T^{8} \) Copy content Toggle raw display
$23$ \( T^{8} \) Copy content Toggle raw display
$29$ \( (T^{4} + 10 T^{3} + \cdots + 10000)^{2} \) Copy content Toggle raw display
$31$ \( T^{8} \) Copy content Toggle raw display
$37$ \( T^{8} + 4 T^{7} + \cdots + 2825761 \) Copy content Toggle raw display
$41$ \( T^{8} - 8 T^{7} + \cdots + 2825761 \) Copy content Toggle raw display
$43$ \( T^{8} \) Copy content Toggle raw display
$47$ \( T^{8} \) Copy content Toggle raw display
$53$ \( T^{8} - 10 T^{7} + \cdots + 10857025 \) Copy content Toggle raw display
$59$ \( T^{8} \) Copy content Toggle raw display
$61$ \( T^{8} + 24 T^{7} + \cdots + 20967241 \) Copy content Toggle raw display
$67$ \( T^{8} \) Copy content Toggle raw display
$71$ \( T^{8} \) Copy content Toggle raw display
$73$ \( T^{8} + 22 T^{7} + \cdots + 9740641 \) Copy content Toggle raw display
$79$ \( T^{8} \) Copy content Toggle raw display
$83$ \( T^{8} \) Copy content Toggle raw display
$89$ \( (T^{4} - 10 T^{3} + \cdots + 10000)^{2} \) Copy content Toggle raw display
$97$ \( T^{8} + 50 T^{7} + \cdots + 639837025 \) Copy content Toggle raw display
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