Properties

Label 18.21.b.a
Level $18$
Weight $21$
Character orbit 18.b
Analytic conductor $45.632$
Analytic rank $0$
Dimension $4$
Inner twists $2$

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Newspace parameters

Copy content comment:Compute space of new eigenforms
 
Copy content gp:[N,k,chi] = [18,21,Mod(17,18)] mf = mfinit([N,k,chi],0) lf = mfeigenbasis(mf)
 
Copy content sage:from sage.modular.dirichlet import DirichletCharacter H = DirichletGroup(18, base_ring=CyclotomicField(2)) chi = DirichletCharacter(H, H._module([1])) N = Newforms(chi, 21, names="a")
 
Copy content magma://Please install CHIMP (https://github.com/edgarcosta/CHIMP) if you want to run this code chi := DirichletCharacter("18.17"); S:= CuspForms(chi, 21); N := Newforms(S);
 
Level: \( N \) \(=\) \( 18 = 2 \cdot 3^{2} \)
Weight: \( k \) \(=\) \( 21 \)
Character orbit: \([\chi]\) \(=\) 18.b (of order \(2\), degree \(1\), minimal)

Newform invariants

Copy content comment:select newform
 
Copy content sage:traces = [4,0,0,-2097152,0,0,196612688] f = next(g for g in N if [g.coefficient(i+1).trace() for i in range(7)] == traces)
 
Copy content gp:f = lf[1] \\ Warning: the index may be different
 
Self dual: no
Analytic conductor: \(45.6324777185\)
Analytic rank: \(0\)
Dimension: \(4\)
Coefficient field: \(\mathbb{Q}[x]/(x^{4} - \cdots)\)
Copy content comment:defining polynomial
 
Copy content gp:f.mod \\ as an extension of the character field
 
Defining polynomial: \( x^{4} - 2x^{3} - 8995x^{2} + 8996x + 20268006 \) Copy content Toggle raw display
Coefficient ring: \(\Z[a_1, \ldots, a_{17}]\)
Coefficient ring index: \( 2^{9}\cdot 3^{10}\cdot 5^{2} \)
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.

\(f(q)\) \(=\) \( q + 512 \beta_1 q^{2} - 524288 q^{4} + ( - 7 \beta_{3} - 793635 \beta_1) q^{5} + ( - \beta_{2} + 49153172) q^{7} - 268435456 \beta_1 q^{8} + (3584 \beta_{2} + 812682240) q^{10} + ( - 21406 \beta_{3} + 6810154692 \beta_1) q^{11}+ \cdots + ( - 100665696256 \beta_{3} - 39\!\cdots\!04 \beta_1) q^{98}+O(q^{100}) \) Copy content Toggle raw display
\(\operatorname{Tr}(f)(q)\) \(=\) \( 4 q - 2097152 q^{4} + 196612688 q^{7} + 3250728960 q^{10} + 311444923136 q^{13} + 1099511627776 q^{16} - 10790450318656 q^{19} - 27894393618432 q^{22} - 290245751476100 q^{25} - 103081672966144 q^{28} - 12\!\cdots\!04 q^{31}+ \cdots - 40\!\cdots\!32 q^{97}+O(q^{100}) \) Copy content Toggle raw display

Basis of coefficient ring in terms of a root \(\nu\) of \( x^{4} - 2x^{3} - 8995x^{2} + 8996x + 20268006 \) : Copy content Toggle raw display

\(\beta_{1}\)\(=\) \( ( 2\nu^{3} - 3\nu^{2} - 8987\nu + 4494 ) / 18009 \) Copy content Toggle raw display
\(\beta_{2}\)\(=\) \( ( -2880\nu^{3} + 4320\nu^{2} + 38874240\nu - 19437840 ) / 667 \) Copy content Toggle raw display
\(\beta_{3}\)\(=\) \( 9720\nu^{2} - 9720\nu - 43720560 \) Copy content Toggle raw display
\(\nu\)\(=\) \( ( \beta_{2} + 38880\beta _1 + 19440 ) / 38880 \) Copy content Toggle raw display
\(\nu^{2}\)\(=\) \( ( 4\beta_{3} + \beta_{2} + 38880\beta _1 + 174901680 ) / 38880 \) Copy content Toggle raw display
\(\nu^{3}\)\(=\) \( ( 6\beta_{3} + 4495\beta_{2} + 524860560\beta _1 + 262342800 ) / 38880 \) Copy content Toggle raw display

Character values

We give the values of \(\chi\) on generators for \(\left(\mathbb{Z}/18\mathbb{Z}\right)^\times\).

\(n\) \(11\)
\(\chi(n)\) \(-1\)

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   \(\iota_m(\nu)\) \( a_{2} \) \( a_{3} \) \( a_{4} \) \( a_{5} \) \( a_{6} \) \( a_{7} \) \( a_{8} \) \( a_{9} \) \( a_{10} \)
17.1
−66.5839 1.41421i
67.5839 1.41421i
67.5839 + 1.41421i
−66.5839 + 1.41421i
724.077i 0 −524288. 1.17877e7i 0 5.17614e7 3.79625e8i 0 −8.53519e9
17.2 724.077i 0 −524288. 1.40324e7i 0 4.65449e7 3.79625e8i 0 1.01606e10
17.3 724.077i 0 −524288. 1.40324e7i 0 4.65449e7 3.79625e8i 0 1.01606e10
17.4 724.077i 0 −524288. 1.17877e7i 0 5.17614e7 3.79625e8i 0 −8.53519e9
\(n\): 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

Twists

       By twisting character orbit
Char Parity Ord Mult Type Twist Min Dim
1.a even 1 1 trivial 18.21.b.a 4
3.b odd 2 1 inner 18.21.b.a 4
    
        By twisted newform orbit
Twist Min Dim Char Parity Ord Mult Type
18.21.b.a 4 1.a even 1 1 trivial
18.21.b.a 4 3.b odd 2 1 inner

Hecke kernels

This newform subspace can be constructed as the kernel of the linear operator \( T_{5}^{4} + 335857739019300T_{5}^{2} + 27360283984671775389120562500 \) acting on \(S_{21}^{\mathrm{new}}(18, [\chi])\). Copy content Toggle raw display

Hecke characteristic polynomials

$p$ $F_p(T)$
$2$ \( (T^{2} + 524288)^{2} \) Copy content Toggle raw display
$3$ \( T^{4} \) Copy content Toggle raw display
$5$ \( T^{4} + \cdots + 27\!\cdots\!00 \) Copy content Toggle raw display
$7$ \( (T^{2} + \cdots + 24\!\cdots\!84)^{2} \) Copy content Toggle raw display
$11$ \( T^{4} + \cdots + 21\!\cdots\!84 \) Copy content Toggle raw display
$13$ \( (T^{2} + \cdots + 44\!\cdots\!56)^{2} \) Copy content Toggle raw display
$17$ \( T^{4} + \cdots + 39\!\cdots\!64 \) Copy content Toggle raw display
$19$ \( (T^{2} + \cdots - 28\!\cdots\!04)^{2} \) Copy content Toggle raw display
$23$ \( T^{4} + \cdots + 56\!\cdots\!84 \) Copy content Toggle raw display
$29$ \( T^{4} + \cdots + 30\!\cdots\!04 \) Copy content Toggle raw display
$31$ \( (T^{2} + \cdots + 63\!\cdots\!76)^{2} \) Copy content Toggle raw display
$37$ \( (T^{2} + \cdots - 17\!\cdots\!76)^{2} \) Copy content Toggle raw display
$41$ \( T^{4} + \cdots + 17\!\cdots\!44 \) Copy content Toggle raw display
$43$ \( (T^{2} + \cdots - 39\!\cdots\!00)^{2} \) Copy content Toggle raw display
$47$ \( T^{4} + \cdots + 17\!\cdots\!00 \) Copy content Toggle raw display
$53$ \( T^{4} + \cdots + 67\!\cdots\!44 \) Copy content Toggle raw display
$59$ \( T^{4} + \cdots + 39\!\cdots\!64 \) Copy content Toggle raw display
$61$ \( (T^{2} + \cdots + 67\!\cdots\!00)^{2} \) Copy content Toggle raw display
$67$ \( (T^{2} + \cdots - 76\!\cdots\!24)^{2} \) Copy content Toggle raw display
$71$ \( T^{4} + \cdots + 23\!\cdots\!44 \) Copy content Toggle raw display
$73$ \( (T^{2} + \cdots - 43\!\cdots\!36)^{2} \) Copy content Toggle raw display
$79$ \( (T^{2} + \cdots + 38\!\cdots\!36)^{2} \) Copy content Toggle raw display
$83$ \( T^{4} + \cdots + 15\!\cdots\!64 \) Copy content Toggle raw display
$89$ \( T^{4} + \cdots + 30\!\cdots\!84 \) Copy content Toggle raw display
$97$ \( (T^{2} + \cdots - 93\!\cdots\!36)^{2} \) Copy content Toggle raw display
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