Properties

Label 21.4.e.a
Level $21$
Weight $4$
Character orbit 21.e
Analytic conductor $1.239$
Analytic rank $0$
Dimension $2$
Inner twists $2$

Related objects

Downloads

Learn more

Show commands: Magma / Pari/GP / SageMath

Newspace parameters

Copy content comment:Compute space of new eigenforms
 
Copy content gp:[N,k,chi] = [21,4,Mod(4,21)] mf = mfinit([N,k,chi],0) lf = mfeigenbasis(mf)
 
Copy content magma://Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code chi := DirichletCharacter("21.4"); S:= CuspForms(chi, 4); N := Newforms(S);
 
Copy content sage:from sage.modular.dirichlet import DirichletCharacter H = DirichletGroup(21, base_ring=CyclotomicField(6)) chi = DirichletCharacter(H, H._module([0, 4])) N = Newforms(chi, 4, names="a")
 
Level: \( N \) \(=\) \( 21 = 3 \cdot 7 \)
Weight: \( k \) \(=\) \( 4 \)
Character orbit: \([\chi]\) \(=\) 21.e (of order \(3\), degree \(2\), minimal)

Newform invariants

Copy content comment:select newform
 
Copy content sage:traces = [2] 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: \(2\)
Coefficient field: \(\Q(\sqrt{-3}) \)
Copy content comment:defining polynomial
 
Copy content gp:f.mod \\ as an extension of the character field
 
Defining polynomial: \( x^{2} - x + 1 \) Copy content Toggle raw display
Coefficient ring: \(\Z[a_1, \ldots, a_{4}]\)
Coefficient ring index: \( 1 \)
Twist minimal: yes
Sato-Tate group: $\mathrm{SU}(2)[C_{3}]$

$q$-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)
 

Coefficients of the \(q\)-expansion are expressed in terms of a primitive root of unity \(\zeta_{6}\). We also show the integral \(q\)-expansion of the trace form.

\(f(q)\) \(=\) \( q + ( - 3 \zeta_{6} + 3) q^{2} - 3 \zeta_{6} q^{3} - \zeta_{6} q^{4} + ( - 3 \zeta_{6} + 3) q^{5} - 9 q^{6} + (21 \zeta_{6} - 14) q^{7} + 21 q^{8} + (9 \zeta_{6} - 9) q^{9} - 9 \zeta_{6} q^{10} + 15 \zeta_{6} q^{11} + \cdots - 135 q^{99} +O(q^{100}) \) Copy content Toggle raw display
\(\operatorname{Tr}(f)(q)\) \(=\) \( 2 q + 3 q^{2} - 3 q^{3} - q^{4} + 3 q^{5} - 18 q^{6} - 7 q^{7} + 42 q^{8} - 9 q^{9} - 9 q^{10} + 15 q^{11} - 3 q^{12} - 128 q^{13} + 84 q^{14} - 18 q^{15} + 71 q^{16} - 84 q^{17} + 27 q^{18} + 16 q^{19}+ \cdots - 270 q^{99}+O(q^{100}) \) Copy content Toggle raw display

Character values

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

\(n\) \(8\) \(10\)
\(\chi(n)\) \(1\) \(-1 + \zeta_{6}\)

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   \(\iota_m(\nu)\) \( a_{2} \) \( a_{3} \) \( a_{4} \) \( a_{5} \) \( a_{6} \) \( a_{7} \) \( a_{8} \) \( a_{9} \) \( a_{10} \)
4.1
0.500000 0.866025i
0.500000 + 0.866025i
1.50000 + 2.59808i −1.50000 + 2.59808i −0.500000 + 0.866025i 1.50000 + 2.59808i −9.00000 −3.50000 18.1865i 21.0000 −4.50000 7.79423i −4.50000 + 7.79423i
16.1 1.50000 2.59808i −1.50000 2.59808i −0.500000 0.866025i 1.50000 2.59808i −9.00000 −3.50000 + 18.1865i 21.0000 −4.50000 + 7.79423i −4.50000 7.79423i
\(n\): e.g. 2-40 or 80-90
Significant digits:
Format:

Inner twists

Char Parity Ord Mult Type
1.a even 1 1 trivial
7.c even 3 1 inner

Twists

       By twisting character orbit
Char Parity Ord Mult Type Twist Min Dim
1.a even 1 1 trivial 21.4.e.a 2
3.b odd 2 1 63.4.e.a 2
4.b odd 2 1 336.4.q.e 2
7.b odd 2 1 147.4.e.h 2
7.c even 3 1 inner 21.4.e.a 2
7.c even 3 1 147.4.a.b 1
7.d odd 6 1 147.4.a.a 1
7.d odd 6 1 147.4.e.h 2
21.c even 2 1 441.4.e.c 2
21.g even 6 1 441.4.a.k 1
21.g even 6 1 441.4.e.c 2
21.h odd 6 1 63.4.e.a 2
21.h odd 6 1 441.4.a.l 1
28.f even 6 1 2352.4.a.bd 1
28.g odd 6 1 336.4.q.e 2
28.g odd 6 1 2352.4.a.i 1
    
        By twisted newform orbit
Twist Min Dim Char Parity Ord Mult Type
21.4.e.a 2 1.a even 1 1 trivial
21.4.e.a 2 7.c even 3 1 inner
63.4.e.a 2 3.b odd 2 1
63.4.e.a 2 21.h odd 6 1
147.4.a.a 1 7.d odd 6 1
147.4.a.b 1 7.c even 3 1
147.4.e.h 2 7.b odd 2 1
147.4.e.h 2 7.d odd 6 1
336.4.q.e 2 4.b odd 2 1
336.4.q.e 2 28.g odd 6 1
441.4.a.k 1 21.g even 6 1
441.4.a.l 1 21.h odd 6 1
441.4.e.c 2 21.c even 2 1
441.4.e.c 2 21.g even 6 1
2352.4.a.i 1 28.g odd 6 1
2352.4.a.bd 1 28.f even 6 1

Hecke kernels

This newform subspace can be constructed as the kernel of the linear operator \( T_{2}^{2} - 3T_{2} + 9 \) acting on \(S_{4}^{\mathrm{new}}(21, [\chi])\). Copy content Toggle raw display

Hecke characteristic polynomials

$p$ $F_p(T)$
$2$ \( T^{2} - 3T + 9 \) Copy content Toggle raw display
$3$ \( T^{2} + 3T + 9 \) Copy content Toggle raw display
$5$ \( T^{2} - 3T + 9 \) Copy content Toggle raw display
$7$ \( T^{2} + 7T + 343 \) Copy content Toggle raw display
$11$ \( T^{2} - 15T + 225 \) Copy content Toggle raw display
$13$ \( (T + 64)^{2} \) Copy content Toggle raw display
$17$ \( T^{2} + 84T + 7056 \) Copy content Toggle raw display
$19$ \( T^{2} - 16T + 256 \) Copy content Toggle raw display
$23$ \( T^{2} - 84T + 7056 \) Copy content Toggle raw display
$29$ \( (T + 297)^{2} \) Copy content Toggle raw display
$31$ \( T^{2} - 253T + 64009 \) Copy content Toggle raw display
$37$ \( T^{2} - 316T + 99856 \) Copy content Toggle raw display
$41$ \( (T - 360)^{2} \) Copy content Toggle raw display
$43$ \( (T - 26)^{2} \) Copy content Toggle raw display
$47$ \( T^{2} - 30T + 900 \) Copy content Toggle raw display
$53$ \( T^{2} + 363T + 131769 \) Copy content Toggle raw display
$59$ \( T^{2} - 15T + 225 \) Copy content Toggle raw display
$61$ \( T^{2} - 118T + 13924 \) Copy content Toggle raw display
$67$ \( T^{2} - 370T + 136900 \) Copy content Toggle raw display
$71$ \( (T + 342)^{2} \) Copy content Toggle raw display
$73$ \( T^{2} + 362T + 131044 \) Copy content Toggle raw display
$79$ \( T^{2} + 467T + 218089 \) Copy content Toggle raw display
$83$ \( (T - 477)^{2} \) Copy content Toggle raw display
$89$ \( T^{2} + 906T + 820836 \) Copy content Toggle raw display
$97$ \( (T - 503)^{2} \) Copy content Toggle raw display
show more
show less