Properties

Label 820.1.o.c
Level $820$
Weight $1$
Character orbit 820.o
Analytic conductor $0.409$
Analytic rank $0$
Dimension $2$
Projective image $D_{4}$
CM discriminant -20
Inner twists $4$

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Newspace parameters

Copy content comment:Compute space of new eigenforms
 
Copy content gp:[N,k,chi] = [820,1,Mod(319,820)] mf = mfinit([N,k,chi],0) lf = mfeigenbasis(mf)
 
Copy content sage:from sage.modular.dirichlet import DirichletCharacter H = DirichletGroup(820, base_ring=CyclotomicField(4)) chi = DirichletCharacter(H, H._module([2, 2, 1])) N = Newforms(chi, 1, names="a")
 
Copy content magma://Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code chi := DirichletCharacter("820.319"); S:= CuspForms(chi, 1); N := Newforms(S);
 
Level: \( N \) \(=\) \( 820 = 2^{2} \cdot 5 \cdot 41 \)
Weight: \( k \) \(=\) \( 1 \)
Character orbit: \([\chi]\) \(=\) 820.o (of order \(4\), degree \(2\), minimal)

Newform invariants

Copy content comment:select newform
 
Copy content sage:traces = [2,0,2] f = next(g for g in N if [g.coefficient(i+1).trace() for i in range(3)] == traces)
 
Copy content gp:f = lf[1] \\ Warning: the index may be different
 
Self dual: no
Analytic conductor: \(0.409233310359\)
Analytic rank: \(0\)
Dimension: \(2\)
Coefficient field: \(\Q(i)\)
Copy content comment:defining polynomial
 
Copy content gp:f.mod \\ as an extension of the character field
 
Defining polynomial: \( x^{2} + 1 \) Copy content Toggle raw display
Coefficient ring: \(\Z[a_1, a_2]\)
Coefficient ring index: \( 1 \)
Twist minimal: yes
Projective image: \(D_{4}\)
Projective field: Galois closure of 4.0.27568400.3

$q$-expansion

Copy content comment:q-expansion
 
Copy content sage:f.q_expansion() # note that sage often uses an isomorphic number field
 
Copy content gp:mfcoefs(f, 20)
 

The \(q\)-expansion and trace form are shown below.

\(f(q)\) \(=\) \( q - i q^{2} + ( - i + 1) q^{3} - q^{4} + i q^{5} + ( - i - 1) q^{6} + ( - i + 1) q^{7} + i q^{8} - i q^{9} + q^{10} + (i - 1) q^{12} + ( - i - 1) q^{14} + (i + 1) q^{15} + q^{16} - q^{18} - i q^{20} + \cdots - q^{98} +O(q^{100}) \) Copy content Toggle raw display
\(\operatorname{Tr}(f)(q)\) \(=\) \( 2 q + 2 q^{3} - 2 q^{4} - 2 q^{6} + 2 q^{7} + 2 q^{10} - 2 q^{12} - 2 q^{14} + 2 q^{15} + 2 q^{16} - 2 q^{18} - 4 q^{23} + 2 q^{24} - 2 q^{25} - 2 q^{28} - 2 q^{29} + 2 q^{30} + 2 q^{35} - 2 q^{40} - 4 q^{42}+ \cdots - 2 q^{98}+O(q^{100}) \) Copy content Toggle raw display

Character values

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

\(n\) \(411\) \(621\) \(657\)
\(\chi(n)\) \(-1\) \(i\) \(-1\)

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.

Copy content comment:embeddings in the coefficient field
 
Copy content gp:mfembed(f)
 
Label   \(\iota_m(\nu)\) \( a_{2} \) \( a_{3} \) \( a_{4} \) \( a_{5} \) \( a_{6} \) \( a_{7} \) \( a_{8} \) \( a_{9} \) \( a_{10} \)
319.1
1.00000i
1.00000i
1.00000i 1.00000 1.00000i −1.00000 1.00000i −1.00000 1.00000i 1.00000 1.00000i 1.00000i 1.00000i 1.00000
419.1 1.00000i 1.00000 + 1.00000i −1.00000 1.00000i −1.00000 + 1.00000i 1.00000 + 1.00000i 1.00000i 1.00000i 1.00000
\(n\): e.g. 2-40 or 990-1000
Significant digits:
Format:

Inner twists

Char Parity Ord Mult Type
1.a even 1 1 trivial
20.d odd 2 1 CM by \(\Q(\sqrt{-5}) \)
41.c even 4 1 inner
820.o odd 4 1 inner

Twists

       By twisting character orbit
Char Parity Ord Mult Type Twist Min Dim
1.a even 1 1 trivial 820.1.o.c yes 2
4.b odd 2 1 820.1.o.b 2
5.b even 2 1 820.1.o.b 2
20.d odd 2 1 CM 820.1.o.c yes 2
41.c even 4 1 inner 820.1.o.c yes 2
164.e odd 4 1 820.1.o.b 2
205.j even 4 1 820.1.o.b 2
820.o odd 4 1 inner 820.1.o.c yes 2
    
        By twisted newform orbit
Twist Min Dim Char Parity Ord Mult Type
820.1.o.b 2 4.b odd 2 1
820.1.o.b 2 5.b even 2 1
820.1.o.b 2 164.e odd 4 1
820.1.o.b 2 205.j even 4 1
820.1.o.c yes 2 1.a even 1 1 trivial
820.1.o.c yes 2 20.d odd 2 1 CM
820.1.o.c yes 2 41.c even 4 1 inner
820.1.o.c yes 2 820.o odd 4 1 inner

Hecke kernels

This newform subspace can be constructed as the intersection of the kernels of the following linear operators acting on \(S_{1}^{\mathrm{new}}(820, [\chi])\):

\( T_{3}^{2} - 2T_{3} + 2 \) Copy content Toggle raw display
\( T_{13} \) Copy content Toggle raw display

Hecke characteristic polynomials

$p$ $F_p(T)$
$2$ \( T^{2} + 1 \) Copy content Toggle raw display
$3$ \( T^{2} - 2T + 2 \) Copy content Toggle raw display
$5$ \( T^{2} + 1 \) Copy content Toggle raw display
$7$ \( T^{2} - 2T + 2 \) Copy content Toggle raw display
$11$ \( T^{2} \) Copy content Toggle raw display
$13$ \( T^{2} \) Copy content Toggle raw display
$17$ \( T^{2} \) Copy content Toggle raw display
$19$ \( T^{2} \) Copy content Toggle raw display
$23$ \( (T + 2)^{2} \) Copy content Toggle raw display
$29$ \( T^{2} + 2T + 2 \) Copy content Toggle raw display
$31$ \( T^{2} \) Copy content Toggle raw display
$37$ \( T^{2} \) Copy content Toggle raw display
$41$ \( T^{2} + 1 \) Copy content Toggle raw display
$43$ \( T^{2} \) Copy content Toggle raw display
$47$ \( T^{2} - 2T + 2 \) Copy content Toggle raw display
$53$ \( T^{2} \) Copy content Toggle raw display
$59$ \( T^{2} \) Copy content Toggle raw display
$61$ \( T^{2} + 4 \) Copy content Toggle raw display
$67$ \( T^{2} + 2T + 2 \) Copy content Toggle raw display
$71$ \( T^{2} \) Copy content Toggle raw display
$73$ \( T^{2} \) Copy content Toggle raw display
$79$ \( T^{2} \) Copy content Toggle raw display
$83$ \( (T - 2)^{2} \) Copy content Toggle raw display
$89$ \( T^{2} + 2T + 2 \) Copy content Toggle raw display
$97$ \( T^{2} \) Copy content Toggle raw display
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