Properties

Label 21.4.c.b
Level $21$
Weight $4$
Character orbit 21.c
Analytic conductor $1.239$
Analytic rank $0$
Dimension $4$
Inner twists $4$

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Newspace parameters

Copy content comment:Compute space of new eigenforms
 
Copy content gp:[N,k,chi] = [21,4,Mod(20,21)] mf = mfinit([N,k,chi],0) lf = mfeigenbasis(mf)
 
Copy content sage:from sage.modular.dirichlet import DirichletCharacter H = DirichletGroup(21, base_ring=CyclotomicField(2)) chi = DirichletCharacter(H, H._module([1, 1])) N = Newforms(chi, 4, names="a")
 
Copy content magma://Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code chi := DirichletCharacter("21.20"); S:= CuspForms(chi, 4); N := Newforms(S);
 
Level: \( N \) \(=\) \( 21 = 3 \cdot 7 \)
Weight: \( k \) \(=\) \( 4 \)
Character orbit: \([\chi]\) \(=\) 21.c (of order \(2\), degree \(1\), minimal)

Newform invariants

Copy content comment:select newform
 
Copy content sage:traces = [4] f = next(g for g in N if [g.coefficient(i+1).trace() for i in range(1)] == traces)
 
Copy content gp:f = lf[1] \\ Warning: the index may be different
 
Self dual: no
Analytic conductor: \(1.23904011012\)
Analytic rank: \(0\)
Dimension: \(4\)
Coefficient field: \(\Q(\sqrt{-6}, \sqrt{-17})\)
Copy content comment:defining polynomial
 
Copy content gp:f.mod \\ as an extension of the character field
 
Defining polynomial: \( x^{4} + 46x^{2} + 121 \) Copy content Toggle raw display
Coefficient ring: \(\Z[a_1, \ldots, a_{5}]\)
Coefficient ring index: \( 1 \)
Twist minimal: yes
Sato-Tate group: $\mathrm{SU}(2)[C_{2}]$

$q$-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)
 

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.

\(f(q)\) \(=\) \( q - \beta_{2} q^{2} + \beta_{3} q^{3} - 9 q^{4} + ( - 2 \beta_{3} - \beta_1) q^{5} + (\beta_{3} + 9 \beta_1) q^{6} + ( - 7 \beta_1 + 7) q^{7} + \beta_{2} q^{8} + (3 \beta_{2} + 24) q^{9} - 17 \beta_1 q^{10}+ \cdots + (192 \beta_{2} - 408) q^{99}+O(q^{100}) \) Copy content Toggle raw display
\(\operatorname{Tr}(f)(q)\) \(=\) \( 4 q - 36 q^{4} + 28 q^{7} + 96 q^{9} - 204 q^{15} - 220 q^{16} + 204 q^{18} - 84 q^{21} + 544 q^{22} - 92 q^{25} - 252 q^{28} - 204 q^{30} - 864 q^{36} + 920 q^{37} + 276 q^{39} + 1428 q^{42} + 176 q^{43}+ \cdots - 1632 q^{99}+O(q^{100}) \) Copy content Toggle raw display

Basis of coefficient ring in terms of a root \(\nu\) of \( x^{4} + 46x^{2} + 121 \) : Copy content Toggle raw display

\(\beta_{1}\)\(=\) \( ( -\nu^{3} - 35\nu ) / 22 \) Copy content Toggle raw display
\(\beta_{2}\)\(=\) \( ( \nu^{3} + 57\nu ) / 22 \) Copy content Toggle raw display
\(\beta_{3}\)\(=\) \( ( \nu^{3} + 11\nu^{2} + 35\nu + 253 ) / 44 \) Copy content Toggle raw display
\(\nu\)\(=\) \( \beta_{2} + \beta_1 \) Copy content Toggle raw display
\(\nu^{2}\)\(=\) \( 4\beta_{3} + 2\beta _1 - 23 \) Copy content Toggle raw display
\(\nu^{3}\)\(=\) \( -35\beta_{2} - 57\beta_1 \) Copy content Toggle raw display

Character values

We give the values of \(\chi\) on generators for \(\left(\mathbb{Z}/21\mathbb{Z}\right)^\times\).

\(n\) \(8\) \(10\)
\(\chi(n)\) \(-1\) \(-1\)

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.

Copy content comment:embeddings in the coefficient field
 
Copy content gp:mfembed(f)
 
Label   \(\iota_m(\nu)\) \( a_{2} \) \( a_{3} \) \( a_{4} \) \( a_{5} \) \( a_{6} \) \( a_{7} \) \( a_{8} \) \( a_{9} \) \( a_{10} \)
20.1
6.57260i
1.67362i
6.57260i
1.67362i
4.12311i −5.04975 1.22474i −9.00000 10.0995 −5.04975 + 20.8207i 7.00000 17.1464i 4.12311i 24.0000 + 12.3693i 41.6413i
20.2 4.12311i 5.04975 + 1.22474i −9.00000 −10.0995 5.04975 20.8207i 7.00000 + 17.1464i 4.12311i 24.0000 + 12.3693i 41.6413i
20.3 4.12311i −5.04975 + 1.22474i −9.00000 10.0995 −5.04975 20.8207i 7.00000 + 17.1464i 4.12311i 24.0000 12.3693i 41.6413i
20.4 4.12311i 5.04975 1.22474i −9.00000 −10.0995 5.04975 + 20.8207i 7.00000 17.1464i 4.12311i 24.0000 12.3693i 41.6413i
\(n\): e.g. 2-40 or 990-1000
Significant digits:
Format:

Inner twists

Char Parity Ord Mult Type
1.a even 1 1 trivial
3.b odd 2 1 inner
7.b odd 2 1 inner
21.c even 2 1 inner

Twists

       By twisting character orbit
Char Parity Ord Mult Type Twist Min Dim
1.a even 1 1 trivial 21.4.c.b 4
3.b odd 2 1 inner 21.4.c.b 4
4.b odd 2 1 336.4.k.b 4
7.b odd 2 1 inner 21.4.c.b 4
7.c even 3 2 147.4.g.c 8
7.d odd 6 2 147.4.g.c 8
12.b even 2 1 336.4.k.b 4
21.c even 2 1 inner 21.4.c.b 4
21.g even 6 2 147.4.g.c 8
21.h odd 6 2 147.4.g.c 8
28.d even 2 1 336.4.k.b 4
84.h odd 2 1 336.4.k.b 4
    
        By twisted newform orbit
Twist Min Dim Char Parity Ord Mult Type
21.4.c.b 4 1.a even 1 1 trivial
21.4.c.b 4 3.b odd 2 1 inner
21.4.c.b 4 7.b odd 2 1 inner
21.4.c.b 4 21.c even 2 1 inner
147.4.g.c 8 7.c even 3 2
147.4.g.c 8 7.d odd 6 2
147.4.g.c 8 21.g even 6 2
147.4.g.c 8 21.h odd 6 2
336.4.k.b 4 4.b odd 2 1
336.4.k.b 4 12.b even 2 1
336.4.k.b 4 28.d even 2 1
336.4.k.b 4 84.h odd 2 1

Hecke kernels

This newform subspace can be constructed as the kernel of the linear operator \( T_{2}^{2} + 17 \) acting on \(S_{4}^{\mathrm{new}}(21, [\chi])\). Copy content Toggle raw display

Hecke characteristic polynomials

$p$ $F_p(T)$
$2$ \( (T^{2} + 17)^{2} \) Copy content Toggle raw display
$3$ \( T^{4} - 48T^{2} + 729 \) Copy content Toggle raw display
$5$ \( (T^{2} - 102)^{2} \) Copy content Toggle raw display
$7$ \( (T^{2} - 14 T + 343)^{2} \) Copy content Toggle raw display
$11$ \( (T^{2} + 1088)^{2} \) Copy content Toggle raw display
$13$ \( (T^{2} + 3174)^{2} \) Copy content Toggle raw display
$17$ \( (T^{2} - 3672)^{2} \) Copy content Toggle raw display
$19$ \( (T^{2} + 1350)^{2} \) Copy content Toggle raw display
$23$ \( (T^{2} + 8228)^{2} \) Copy content Toggle raw display
$29$ \( (T^{2} + 3332)^{2} \) Copy content Toggle raw display
$31$ \( (T^{2} + 64896)^{2} \) Copy content Toggle raw display
$37$ \( (T - 230)^{4} \) Copy content Toggle raw display
$41$ \( (T^{2} - 19992)^{2} \) Copy content Toggle raw display
$43$ \( (T - 44)^{4} \) Copy content Toggle raw display
$47$ \( (T^{2} - 117912)^{2} \) Copy content Toggle raw display
$53$ \( (T^{2} + 42500)^{2} \) Copy content Toggle raw display
$59$ \( (T^{2} - 17238)^{2} \) Copy content Toggle raw display
$61$ \( (T^{2} + 5046)^{2} \) Copy content Toggle raw display
$67$ \( (T + 64)^{4} \) Copy content Toggle raw display
$71$ \( (T^{2} + 213248)^{2} \) Copy content Toggle raw display
$73$ \( (T^{2} + 7776)^{2} \) Copy content Toggle raw display
$79$ \( (T + 442)^{4} \) Copy content Toggle raw display
$83$ \( (T^{2} - 244902)^{2} \) Copy content Toggle raw display
$89$ \( (T^{2} - 235008)^{2} \) Copy content Toggle raw display
$97$ \( (T^{2} + 1193496)^{2} \) Copy content Toggle raw display
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