gp: [N,k,chi] = [1840,2,Mod(1839,1840)]
mf = mfinit([N,k,chi],0)
lf = mfeigenbasis(mf)
sage: from sage.modular.dirichlet import DirichletCharacter
H = DirichletGroup(1840, base_ring=CyclotomicField(2))
chi = DirichletCharacter(H, H._module([1, 0, 1, 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("1840.1839");
S:= CuspForms(chi, 2);
N := Newforms(S);
Newform invariants
sage: traces = [4,0,-4,0,0,0,0,0,-8]
f = next(g for g in N if [g.coefficient(i+1).trace() for i in range(9)] == 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 in terms of a root ν \nu ν of
x 4 + 4 x 2 + 25 x^{4} + 4x^{2} + 25 x 4 + 4 x 2 + 2 5
x^4 + 4*x^2 + 25
:
β 1 \beta_{1} β 1 = = =
ν \nu ν
v
β 2 \beta_{2} β 2 = = =
( ν 3 + 4 ν ) / 5 ( \nu^{3} + 4\nu ) / 5 ( ν 3 + 4 ν ) / 5
(v^3 + 4*v) / 5
β 3 \beta_{3} β 3 = = =
ν 2 + 2 \nu^{2} + 2 ν 2 + 2
v^2 + 2
ν \nu ν = = =
β 1 \beta_1 β 1
b1
ν 2 \nu^{2} ν 2 = = =
β 3 − 2 \beta_{3} - 2 β 3 − 2
b3 - 2
ν 3 \nu^{3} ν 3 = = =
5 β 2 − 4 β 1 5\beta_{2} - 4\beta_1 5 β 2 − 4 β 1
5*b2 - 4*b1
Character values
We give the values of χ \chi χ on generators for ( Z / 1840 Z ) × \left(\mathbb{Z}/1840\mathbb{Z}\right)^\times ( Z / 1 8 4 0 Z ) × .
n n n
737 737 7 3 7
1151 1151 1 1 5 1
1201 1201 1 2 0 1
1381 1381 1 3 8 1
χ ( n ) \chi(n) χ ( n )
− 1 -1 − 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 ( 1840 , [ χ ] ) S_{2}^{\mathrm{new}}(1840, [\chi]) S 2 n e w ( 1 8 4 0 , [ χ ] ) :
T 3 + 1 T_{3} + 1 T 3 + 1
T3 + 1
T 7 T_{7} T 7
T7
p p p
F p ( T ) F_p(T) F p ( T )
2 2 2
T 4 T^{4} T 4
T^4
3 3 3
( T + 1 ) 4 (T + 1)^{4} ( T + 1 ) 4
(T + 1)^4
5 5 5
T 4 + 4 T 2 + 25 T^{4} + 4T^{2} + 25 T 4 + 4 T 2 + 2 5
T^4 + 4*T^2 + 25
7 7 7
T 4 T^{4} T 4
T^4
11 11 1 1
( T 2 − 24 ) 2 (T^{2} - 24)^{2} ( T 2 − 2 4 ) 2
(T^2 - 24)^2
13 13 1 3
( T 2 + 21 ) 2 (T^{2} + 21)^{2} ( T 2 + 2 1 ) 2
(T^2 + 21)^2
17 17 1 7
( T 2 − 6 ) 2 (T^{2} - 6)^{2} ( T 2 − 6 ) 2
(T^2 - 6)^2
19 19 1 9
( T 2 − 6 ) 2 (T^{2} - 6)^{2} ( T 2 − 6 ) 2
(T^2 - 6)^2
23 23 2 3
( T 2 − 6 T + 23 ) 2 (T^{2} - 6 T + 23)^{2} ( T 2 − 6 T + 2 3 ) 2
(T^2 - 6*T + 23)^2
29 29 2 9
( T + 3 ) 4 (T + 3)^{4} ( T + 3 ) 4
(T + 3)^4
31 31 3 1
( T 2 + 21 ) 2 (T^{2} + 21)^{2} ( T 2 + 2 1 ) 2
(T^2 + 21)^2
37 37 3 7
( T 2 − 24 ) 2 (T^{2} - 24)^{2} ( T 2 − 2 4 ) 2
(T^2 - 24)^2
41 41 4 1
( T + 3 ) 4 (T + 3)^{4} ( T + 3 ) 4
(T + 3)^4
43 43 4 3
( T 2 + 126 ) 2 (T^{2} + 126)^{2} ( T 2 + 1 2 6 ) 2
(T^2 + 126)^2
47 47 4 7
( T − 9 ) 4 (T - 9)^{4} ( T − 9 ) 4
(T - 9)^4
53 53 5 3
( T 2 − 24 ) 2 (T^{2} - 24)^{2} ( T 2 − 2 4 ) 2
(T^2 - 24)^2
59 59 5 9
( T 2 + 84 ) 2 (T^{2} + 84)^{2} ( T 2 + 8 4 ) 2
(T^2 + 84)^2
61 61 6 1
( T 2 + 126 ) 2 (T^{2} + 126)^{2} ( T 2 + 1 2 6 ) 2
(T^2 + 126)^2
67 67 6 7
T 4 T^{4} T 4
T^4
71 71 7 1
( T 2 + 189 ) 2 (T^{2} + 189)^{2} ( T 2 + 1 8 9 ) 2
(T^2 + 189)^2
73 73 7 3
( T 2 + 21 ) 2 (T^{2} + 21)^{2} ( T 2 + 2 1 ) 2
(T^2 + 21)^2
79 79 7 9
( T 2 − 54 ) 2 (T^{2} - 54)^{2} ( T 2 − 5 4 ) 2
(T^2 - 54)^2
83 83 8 3
( T 2 + 14 ) 2 (T^{2} + 14)^{2} ( T 2 + 1 4 ) 2
(T^2 + 14)^2
89 89 8 9
( T 2 + 14 ) 2 (T^{2} + 14)^{2} ( T 2 + 1 4 ) 2
(T^2 + 14)^2
97 97 9 7
( T 2 − 96 ) 2 (T^{2} - 96)^{2} ( T 2 − 9 6 ) 2
(T^2 - 96)^2
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