Properties

Label 18.0.163...043.1
Degree $18$
Signature $[0, 9]$
Discriminant $-1.637\times 10^{19}$
Root discriminant \(11.68\)
Ramified primes $3,43$
Class number $1$
Class group trivial
Galois group $S_3^2:C_6$ (as 18T93)

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Show commands: Magma / Oscar / PariGP / SageMath

Normalized defining polynomial

sage: x = polygen(QQ); K.<a> = NumberField(x^18 - 3*x^15 - 3*x^12 + 20*x^9 + 33*x^6 - 12*x^3 + 1)
 
gp: K = bnfinit(y^18 - 3*y^15 - 3*y^12 + 20*y^9 + 33*y^6 - 12*y^3 + 1, 1)
 
magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(x^18 - 3*x^15 - 3*x^12 + 20*x^9 + 33*x^6 - 12*x^3 + 1);
 
oscar: Qx, x = PolynomialRing(QQ); K, a = NumberField(x^18 - 3*x^15 - 3*x^12 + 20*x^9 + 33*x^6 - 12*x^3 + 1)
 

\( x^{18} - 3x^{15} - 3x^{12} + 20x^{9} + 33x^{6} - 12x^{3} + 1 \) Copy content Toggle raw display

sage: K.defining_polynomial()
 
gp: K.pol
 
magma: DefiningPolynomial(K);
 
oscar: defining_polynomial(K)
 

Invariants

Degree:  $18$
sage: K.degree()
 
gp: poldegree(K.pol)
 
magma: Degree(K);
 
oscar: degree(K)
 
Signature:  $[0, 9]$
sage: K.signature()
 
gp: K.sign
 
magma: Signature(K);
 
oscar: signature(K)
 
Discriminant:   \(-16369786239449258043\) \(\medspace = -\,3^{30}\cdot 43^{3}\) Copy content Toggle raw display
sage: K.disc()
 
gp: K.disc
 
magma: OK := Integers(K); Discriminant(OK);
 
oscar: OK = ring_of_integers(K); discriminant(OK)
 
Root discriminant:  \(11.68\)
sage: (K.disc().abs())^(1./K.degree())
 
gp: abs(K.disc)^(1/poldegree(K.pol))
 
magma: Abs(Discriminant(OK))^(1/Degree(K));
 
oscar: (1.0 * dK)^(1/degree(K))
 
Galois root discriminant:  $3^{187/108}43^{1/2}\approx 43.94008014870428$
Ramified primes:   \(3\), \(43\) Copy content Toggle raw display
sage: K.disc().support()
 
gp: factor(abs(K.disc))[,1]~
 
magma: PrimeDivisors(Discriminant(OK));
 
oscar: prime_divisors(discriminant((OK)))
 
Discriminant root field:  \(\Q(\sqrt{-43}) \)
$\card{ \Aut(K/\Q) }$:  $3$
sage: K.automorphisms()
 
magma: Automorphisms(K);
 
oscar: automorphisms(K)
 
This field is not Galois over $\Q$.
This is not a CM field.

Integral basis (with respect to field generator \(a\))

$1$, $a$, $a^{2}$, $a^{3}$, $a^{4}$, $a^{5}$, $\frac{1}{3}a^{6}-\frac{1}{3}a^{3}+\frac{1}{3}$, $\frac{1}{3}a^{7}-\frac{1}{3}a^{4}+\frac{1}{3}a$, $\frac{1}{3}a^{8}-\frac{1}{3}a^{5}+\frac{1}{3}a^{2}$, $\frac{1}{3}a^{9}+\frac{1}{3}$, $\frac{1}{3}a^{10}+\frac{1}{3}a$, $\frac{1}{9}a^{11}-\frac{1}{9}a^{10}+\frac{1}{9}a^{9}+\frac{1}{9}a^{2}-\frac{1}{9}a+\frac{1}{9}$, $\frac{1}{9}a^{12}+\frac{1}{9}a^{9}+\frac{1}{9}a^{3}+\frac{1}{9}$, $\frac{1}{9}a^{13}+\frac{1}{9}a^{10}+\frac{1}{9}a^{4}+\frac{1}{9}a$, $\frac{1}{9}a^{14}+\frac{1}{9}a^{10}-\frac{1}{9}a^{9}+\frac{1}{9}a^{5}+\frac{1}{9}a-\frac{1}{9}$, $\frac{1}{9}a^{15}-\frac{1}{9}a^{9}+\frac{1}{9}a^{6}-\frac{1}{9}$, $\frac{1}{27}a^{16}+\frac{1}{27}a^{15}-\frac{1}{27}a^{13}-\frac{1}{27}a^{12}+\frac{1}{27}a^{10}+\frac{1}{27}a^{9}+\frac{1}{27}a^{7}+\frac{1}{27}a^{6}-\frac{1}{27}a^{4}-\frac{1}{27}a^{3}+\frac{1}{27}a+\frac{1}{27}$, $\frac{1}{27}a^{17}-\frac{1}{27}a^{15}-\frac{1}{27}a^{14}+\frac{1}{27}a^{12}+\frac{1}{27}a^{11}-\frac{1}{27}a^{9}+\frac{1}{27}a^{8}-\frac{1}{27}a^{6}-\frac{1}{27}a^{5}+\frac{1}{27}a^{3}+\frac{1}{27}a^{2}-\frac{1}{27}$ Copy content Toggle raw display

sage: K.integral_basis()
 
gp: K.zk
 
magma: IntegralBasis(K);
 
oscar: basis(OK)
 

Monogenic:  Not computed
Index:  $1$
Inessential primes:  None

Class group and class number

Trivial group, which has order $1$

sage: K.class_group().invariants()
 
gp: K.clgp
 
magma: ClassGroup(K);
 
oscar: class_group(K)
 

Unit group

sage: UK = K.unit_group()
 
magma: UK, fUK := UnitGroup(K);
 
oscar: UK, fUK = unit_group(OK)
 
Rank:  $8$
sage: UK.rank()
 
gp: K.fu
 
magma: UnitRank(K);
 
oscar: rank(UK)
 
Torsion generator:   \( \frac{16}{3} a^{17} - \frac{137}{9} a^{14} - \frac{164}{9} a^{11} + 104 a^{8} + \frac{1720}{9} a^{5} - \frac{320}{9} a^{2} \)  (order $18$) Copy content Toggle raw display
sage: UK.torsion_generator()
 
gp: K.tu[2]
 
magma: K!f(TU.1) where TU,f is TorsionUnitGroup(K);
 
oscar: torsion_units_generator(OK)
 
Fundamental units:   $\frac{4}{9}a^{15}-\frac{11}{9}a^{12}-\frac{5}{3}a^{9}+\frac{79}{9}a^{6}+\frac{148}{9}a^{3}-\frac{7}{3}$, $4a^{17}+\frac{28}{27}a^{16}-\frac{26}{27}a^{15}-\frac{34}{3}a^{14}-\frac{79}{27}a^{13}+\frac{74}{27}a^{12}-\frac{125}{9}a^{11}-\frac{98}{27}a^{10}+\frac{88}{27}a^{9}+\frac{233}{3}a^{8}+\frac{541}{27}a^{7}-\frac{503}{27}a^{6}+145a^{5}+\frac{1028}{27}a^{4}-\frac{934}{27}a^{3}-\frac{218}{9}a^{2}-\frac{152}{27}a+\frac{151}{27}$, $\frac{11}{3}a^{17}-\frac{28}{27}a^{16}+\frac{8}{27}a^{15}-\frac{94}{9}a^{14}+\frac{79}{27}a^{13}-\frac{23}{27}a^{12}-\frac{113}{9}a^{11}+\frac{98}{27}a^{10}-\frac{28}{27}a^{9}+\frac{214}{3}a^{8}-\frac{541}{27}a^{7}+\frac{161}{27}a^{6}+\frac{1187}{9}a^{5}-\frac{1028}{27}a^{4}+\frac{283}{27}a^{3}-\frac{215}{9}a^{2}+\frac{152}{27}a-\frac{64}{27}$, $\frac{13}{9}a^{15}-\frac{37}{9}a^{12}-\frac{44}{9}a^{9}+\frac{250}{9}a^{6}+\frac{473}{9}a^{3}-\frac{77}{9}$, $\frac{73}{27}a^{17}+\frac{43}{27}a^{16}-\frac{208}{27}a^{14}-\frac{121}{27}a^{13}-\frac{251}{27}a^{11}-\frac{152}{27}a^{10}+\frac{1423}{27}a^{8}+\frac{835}{27}a^{7}+\frac{2627}{27}a^{5}+\frac{1571}{27}a^{4}-\frac{494}{27}a^{2}-\frac{224}{27}a$, $\frac{107}{27}a^{17}-\frac{46}{27}a^{16}-\frac{2}{3}a^{15}-\frac{305}{27}a^{14}+\frac{130}{27}a^{13}+\frac{17}{9}a^{12}-\frac{367}{27}a^{11}+\frac{161}{27}a^{10}+\frac{7}{3}a^{9}+\frac{2087}{27}a^{8}-\frac{892}{27}a^{7}-13a^{6}+\frac{3844}{27}a^{5}-\frac{1670}{27}a^{4}-\frac{214}{9}a^{3}-\frac{709}{27}a^{2}+\frac{260}{27}a+4$, $\frac{100}{27}a^{17}+4a^{16}+\frac{26}{27}a^{15}-\frac{283}{27}a^{14}-\frac{34}{3}a^{13}-\frac{74}{27}a^{12}-\frac{347}{27}a^{11}-\frac{125}{9}a^{10}-\frac{88}{27}a^{9}+\frac{1936}{27}a^{8}+\frac{233}{3}a^{7}+\frac{503}{27}a^{6}+\frac{3632}{27}a^{5}+145a^{4}+\frac{934}{27}a^{3}-\frac{563}{27}a^{2}-\frac{218}{9}a-\frac{151}{27}$, $\frac{71}{27}a^{16}-\frac{43}{27}a^{15}-\frac{203}{27}a^{13}+\frac{121}{27}a^{12}-\frac{241}{27}a^{10}+\frac{152}{27}a^{9}+\frac{1385}{27}a^{7}-\frac{835}{27}a^{6}+\frac{2533}{27}a^{4}-\frac{1571}{27}a^{3}-\frac{493}{27}a+\frac{251}{27}$ Copy content Toggle raw display
sage: UK.fundamental_units()
 
gp: K.fu
 
magma: [K|fUK(g): g in Generators(UK)];
 
oscar: [K(fUK(a)) for a in gens(UK)]
 
Regulator:  \( 1206.62977052 \)
sage: K.regulator()
 
gp: K.reg
 
magma: Regulator(K);
 
oscar: regulator(K)
 

Class number formula

\[ \begin{aligned}\lim_{s\to 1} (s-1)\zeta_K(s) =\mathstrut & \frac{2^{r_1}\cdot (2\pi)^{r_2}\cdot R\cdot h}{w\cdot\sqrt{|D|}}\cr \approx\mathstrut &\frac{2^{0}\cdot(2\pi)^{9}\cdot 1206.62977052 \cdot 1}{18\cdot\sqrt{16369786239449258043}}\cr\approx \mathstrut & 0.252870892961 \end{aligned}\]

# self-contained SageMath code snippet to compute the analytic class number formula
 
x = polygen(QQ); K.<a> = NumberField(x^18 - 3*x^15 - 3*x^12 + 20*x^9 + 33*x^6 - 12*x^3 + 1)
 
DK = K.disc(); r1,r2 = K.signature(); RK = K.regulator(); RR = RK.parent()
 
hK = K.class_number(); wK = K.unit_group().torsion_generator().order();
 
2^r1 * (2*RR(pi))^r2 * RK * hK / (wK * RR(sqrt(abs(DK))))
 
# self-contained Pari/GP code snippet to compute the analytic class number formula
 
K = bnfinit(x^18 - 3*x^15 - 3*x^12 + 20*x^9 + 33*x^6 - 12*x^3 + 1, 1);
 
[polcoeff (lfunrootres (lfuncreate (K))[1][1][2], -1), 2^K.r1 * (2*Pi)^K.r2 * K.reg * K.no / (K.tu[1] * sqrt (abs (K.disc)))]
 
/* self-contained Magma code snippet to compute the analytic class number formula */
 
Qx<x> := PolynomialRing(QQ); K<a> := NumberField(x^18 - 3*x^15 - 3*x^12 + 20*x^9 + 33*x^6 - 12*x^3 + 1);
 
OK := Integers(K); DK := Discriminant(OK);
 
UK, fUK := UnitGroup(OK); clK, fclK := ClassGroup(OK);
 
r1,r2 := Signature(K); RK := Regulator(K); RR := Parent(RK);
 
hK := #clK; wK := #TorsionSubgroup(UK);
 
2^r1 * (2*Pi(RR))^r2 * RK * hK / (wK * Sqrt(RR!Abs(DK)));
 
# self-contained Oscar code snippet to compute the analytic class number formula
 
Qx, x = PolynomialRing(QQ); K, a = NumberField(x^18 - 3*x^15 - 3*x^12 + 20*x^9 + 33*x^6 - 12*x^3 + 1);
 
OK = ring_of_integers(K); DK = discriminant(OK);
 
UK, fUK = unit_group(OK); clK, fclK = class_group(OK);
 
r1,r2 = signature(K); RK = regulator(K); RR = parent(RK);
 
hK = order(clK); wK = torsion_units_order(K);
 
2^r1 * (2*pi)^r2 * RK * hK / (wK * sqrt(RR(abs(DK))))
 

Galois group

$S_3^2:C_6$ (as 18T93):

sage: K.galois_group(type='pari')
 
gp: polgalois(K.pol)
 
magma: G = GaloisGroup(K);
 
oscar: G, Gtx = galois_group(K); G, transitive_group_identification(G)
 
A solvable group of order 216
The 27 conjugacy class representatives for $S_3^2:C_6$
Character table for $S_3^2:C_6$

Intermediate fields

\(\Q(\sqrt{-3}) \), \(\Q(\zeta_{9})^+\), \(\Q(\zeta_{9})\), 6.0.31347.1

Fields in the database are given up to isomorphism. Isomorphic intermediate fields are shown with their multiplicities.

sage: K.subfields()[1:-1]
 
gp: L = nfsubfields(K); L[2..length(b)]
 
magma: L := Subfields(K); L[2..#L];
 
oscar: subfields(K)[2:end-1]
 

Sibling fields

Degree 12 siblings: data not computed
Degree 18 sibling: data not computed
Degree 24 siblings: data not computed
Degree 27 sibling: data not computed
Degree 36 siblings: data not computed
Minimal sibling: 12.0.92407922456769.1

Frobenius cycle types

$p$ $2$ $3$ $5$ $7$ $11$ $13$ $17$ $19$ $23$ $29$ $31$ $37$ $41$ $43$ $47$ $53$ $59$
Cycle type ${\href{/padicField/2.6.0.1}{6} }^{3}$ R ${\href{/padicField/5.6.0.1}{6} }^{3}$ ${\href{/padicField/7.6.0.1}{6} }{,}\,{\href{/padicField/7.3.0.1}{3} }^{4}$ ${\href{/padicField/11.12.0.1}{12} }{,}\,{\href{/padicField/11.6.0.1}{6} }$ ${\href{/padicField/13.6.0.1}{6} }^{2}{,}\,{\href{/padicField/13.3.0.1}{3} }^{2}$ ${\href{/padicField/17.4.0.1}{4} }^{3}{,}\,{\href{/padicField/17.2.0.1}{2} }^{3}$ ${\href{/padicField/19.3.0.1}{3} }^{3}{,}\,{\href{/padicField/19.2.0.1}{2} }^{3}{,}\,{\href{/padicField/19.1.0.1}{1} }^{3}$ ${\href{/padicField/23.12.0.1}{12} }{,}\,{\href{/padicField/23.6.0.1}{6} }$ ${\href{/padicField/29.6.0.1}{6} }^{3}$ ${\href{/padicField/31.6.0.1}{6} }^{2}{,}\,{\href{/padicField/31.3.0.1}{3} }^{2}$ ${\href{/padicField/37.3.0.1}{3} }^{3}{,}\,{\href{/padicField/37.2.0.1}{2} }^{3}{,}\,{\href{/padicField/37.1.0.1}{1} }^{3}$ ${\href{/padicField/41.12.0.1}{12} }{,}\,{\href{/padicField/41.6.0.1}{6} }$ R ${\href{/padicField/47.12.0.1}{12} }{,}\,{\href{/padicField/47.6.0.1}{6} }$ ${\href{/padicField/53.4.0.1}{4} }^{3}{,}\,{\href{/padicField/53.2.0.1}{2} }^{3}$ ${\href{/padicField/59.12.0.1}{12} }{,}\,{\href{/padicField/59.6.0.1}{6} }$

In the table, R denotes a ramified prime. Cycle lengths which are repeated in a cycle type are indicated by exponents.

# to obtain a list of $[e_i,f_i]$ for the factorization of the ideal $p\mathcal{O}_K$ for $p=7$ in Sage:
 
p = 7; [(e, pr.norm().valuation(p)) for pr,e in K.factor(p)]
 
\\ to obtain a list of $[e_i,f_i]$ for the factorization of the ideal $p\mathcal{O}_K$ for $p=7$ in Pari:
 
p = 7; pfac = idealprimedec(K, p); vector(length(pfac), j, [pfac[j][3], pfac[j][4]])
 
// to obtain a list of $[e_i,f_i]$ for the factorization of the ideal $p\mathcal{O}_K$ for $p=7 in Magma:
 
p := 7; [<pr[2], Valuation(Norm(pr[1]), p)> : pr in Factorization(p*Integers(K))];
 
# to obtain a list of $[e_i,f_i]$ for the factorization of the ideal $p\mathcal{O}_K$ for $p=7$ in Oscar:
 
p = 7; pfac = factor(ideal(ring_of_integers(K), p)); [(e, valuation(norm(pr),p)) for (pr,e) in pfac]
 

Local algebras for ramified primes

$p$LabelPolynomial $e$ $f$ $c$ Galois group Slope content
\(3\) Copy content Toggle raw display Deg $18$$18$$1$$30$
\(43\) Copy content Toggle raw display 43.3.0.1$x^{3} + x + 40$$1$$3$$0$$C_3$$[\ ]^{3}$
43.3.0.1$x^{3} + x + 40$$1$$3$$0$$C_3$$[\ ]^{3}$
43.6.3.1$x^{6} + 1849 x^{2} - 3180280$$2$$3$$3$$C_6$$[\ ]_{2}^{3}$
43.6.0.1$x^{6} + 19 x^{3} + 28 x^{2} + 21 x + 3$$1$$6$$0$$C_6$$[\ ]^{6}$