gp: [N,k,chi] = [936,2,Mod(307,936)]
mf = mfinit([N,k,chi],0)
lf = mfeigenbasis(mf)
sage: from sage.modular.dirichlet import DirichletCharacter
H = DirichletGroup(936, base_ring=CyclotomicField(4))
chi = DirichletCharacter(H, H._module([2, 2, 0, 1]))
N = Newforms(chi, 2, names="a")
magma: //Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code
chi := DirichletCharacter("936.307");
S:= CuspForms(chi, 2);
N := Newforms(S);
Newform invariants
sage: traces = [4,0,0,-8,0,0,4]
f = next(g for g in N if [g.coefficient(i+1).trace() for i in range(7)] == traces)
gp: f = lf[1] \\ Warning: the index may be different
sage: f.q_expansion() # note that sage often uses an isomorphic number field
gp: mfcoefs(f, 20)
Coefficients of the q q q -expansion are expressed in terms of a basis 1 , β 1 , β 2 , β 3 1,\beta_1,\beta_2,\beta_3 1 , β 1 , β 2 , β 3 for the coefficient ring described below.
We also show the integral q q q -expansion of the trace form .
Basis of coefficient ring
β 1 \beta_{1} β 1 = = =
ζ 8 2 \zeta_{8}^{2} ζ 8 2
v^2
β 2 \beta_{2} β 2 = = =
ζ 8 3 + ζ 8 \zeta_{8}^{3} + \zeta_{8} ζ 8 3 + ζ 8
v^3 + v
β 3 \beta_{3} β 3 = = =
− ζ 8 3 + ζ 8 -\zeta_{8}^{3} + \zeta_{8} − ζ 8 3 + ζ 8
-v^3 + v
ζ 8 \zeta_{8} ζ 8 = = =
( β 3 + β 2 ) / 2 ( \beta_{3} + \beta_{2} ) / 2 ( β 3 + β 2 ) / 2
(b3 + b2) / 2
ζ 8 2 \zeta_{8}^{2} ζ 8 2 = = =
β 1 \beta_1 β 1
b1
ζ 8 3 \zeta_{8}^{3} ζ 8 3 = = =
( − β 3 + β 2 ) / 2 ( -\beta_{3} + \beta_{2} ) / 2 ( − β 3 + β 2 ) / 2
(-b3 + b2) / 2
Character values
We give the values of χ \chi χ on generators for ( Z / 936 Z ) × \left(\mathbb{Z}/936\mathbb{Z}\right)^\times ( Z / 9 3 6 Z ) × .
n n n
145 145 1 4 5
209 209 2 0 9
469 469 4 6 9
703 703 7 0 3
χ ( n ) \chi(n) χ ( n )
− β 1 -\beta_{1} − β 1
1 1 1
− 1 -1 − 1
− 1 -1 − 1
For each embedding ι m \iota_m ι m of the coefficient field, the values ι m ( a n ) \iota_m(a_n) ι m ( a n ) are shown below.
For more information on an embedded modular form you can click on its label.
gp: mfembed(f)
Refresh table
This newform subspace can be constructed as the intersection of the kernels of the following linear operators acting on S 2 n e w ( 936 , [ χ ] ) S_{2}^{\mathrm{new}}(936, [\chi]) S 2 n e w ( 9 3 6 , [ χ ] ) :
T 5 4 + 256 T_{5}^{4} + 256 T 5 4 + 2 5 6
T5^4 + 256
T 7 2 − 2 T 7 + 2 T_{7}^{2} - 2T_{7} + 2 T 7 2 − 2 T 7 + 2
T7^2 - 2*T7 + 2
p p p
F p ( T ) F_p(T) F p ( T )
2 2 2
( T 2 + 2 ) 2 (T^{2} + 2)^{2} ( T 2 + 2 ) 2
(T^2 + 2)^2
3 3 3
T 4 T^{4} T 4
T^4
5 5 5
T 4 + 256 T^{4} + 256 T 4 + 2 5 6
T^4 + 256
7 7 7
( T 2 − 2 T + 2 ) 2 (T^{2} - 2 T + 2)^{2} ( T 2 − 2 T + 2 ) 2
(T^2 - 2*T + 2)^2
11 11 1 1
T 4 + 16 T^{4} + 16 T 4 + 1 6
T^4 + 16
13 13 1 3
( T 2 + 4 T + 13 ) 2 (T^{2} + 4 T + 13)^{2} ( T 2 + 4 T + 1 3 ) 2
(T^2 + 4*T + 13)^2
17 17 1 7
( T 2 + 8 ) 2 (T^{2} + 8)^{2} ( T 2 + 8 ) 2
(T^2 + 8)^2
19 19 1 9
( T 2 − 2 T + 2 ) 2 (T^{2} - 2 T + 2)^{2} ( T 2 − 2 T + 2 ) 2
(T^2 - 2*T + 2)^2
23 23 2 3
( T 2 − 72 ) 2 (T^{2} - 72)^{2} ( T 2 − 7 2 ) 2
(T^2 - 72)^2
29 29 2 9
( T 2 + 32 ) 2 (T^{2} + 32)^{2} ( T 2 + 3 2 ) 2
(T^2 + 32)^2
31 31 3 1
( T 2 − 14 T + 98 ) 2 (T^{2} - 14 T + 98)^{2} ( T 2 − 1 4 T + 9 8 ) 2
(T^2 - 14*T + 98)^2
37 37 3 7
( T 2 + 10 T + 50 ) 2 (T^{2} + 10 T + 50)^{2} ( T 2 + 1 0 T + 5 0 ) 2
(T^2 + 10*T + 50)^2
41 41 4 1
T 4 + 4096 T^{4} + 4096 T 4 + 4 0 9 6
T^4 + 4096
43 43 4 3
T 4 T^{4} T 4
T^4
47 47 4 7
T 4 + 16 T^{4} + 16 T 4 + 1 6
T^4 + 16
53 53 5 3
( T 2 + 8 ) 2 (T^{2} + 8)^{2} ( T 2 + 8 ) 2
(T^2 + 8)^2
59 59 5 9
T 4 + 10000 T^{4} + 10000 T 4 + 1 0 0 0 0
T^4 + 10000
61 61 6 1
( T 2 + 36 ) 2 (T^{2} + 36)^{2} ( T 2 + 3 6 ) 2
(T^2 + 36)^2
67 67 6 7
( T 2 + 10 T + 50 ) 2 (T^{2} + 10 T + 50)^{2} ( T 2 + 1 0 T + 5 0 ) 2
(T^2 + 10*T + 50)^2
71 71 7 1
T 4 + 38416 T^{4} + 38416 T 4 + 3 8 4 1 6
T^4 + 38416
73 73 7 3
( T 2 − 14 T + 98 ) 2 (T^{2} - 14 T + 98)^{2} ( T 2 − 1 4 T + 9 8 ) 2
(T^2 - 14*T + 98)^2
79 79 7 9
( T 2 + 36 ) 2 (T^{2} + 36)^{2} ( T 2 + 3 6 ) 2
(T^2 + 36)^2
83 83 8 3
T 4 + 38416 T^{4} + 38416 T 4 + 3 8 4 1 6
T^4 + 38416
89 89 8 9
T 4 + 4096 T^{4} + 4096 T 4 + 4 0 9 6
T^4 + 4096
97 97 9 7
( T 2 − 14 T + 98 ) 2 (T^{2} - 14 T + 98)^{2} ( T 2 − 1 4 T + 9 8 ) 2
(T^2 - 14*T + 98)^2
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