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Properties

Label 18.0.30678065370...7719.1
Degree $18$
Signature $[0, 9]$
Discriminant $-\,7^{9}\cdot 97^{9}$
Root discriminant $26.06$
Ramified primes $7, 97$
Class number $2$
Class group $[2]$
Galois group $D_9$ (as 18T5)

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Show commands for: Magma / SageMath / Pari/GP

magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![679, 0, -2225, 0, 915, 0, 2724, 0, -2522, 0, 1054, 0, -240, 0, 57, 0, -2, 0, 1]);
 
sage: x = polygen(QQ); K.<a> = NumberField(x^18 - 2*x^16 + 57*x^14 - 240*x^12 + 1054*x^10 - 2522*x^8 + 2724*x^6 + 915*x^4 - 2225*x^2 + 679)
 
gp: K = bnfinit(x^18 - 2*x^16 + 57*x^14 - 240*x^12 + 1054*x^10 - 2522*x^8 + 2724*x^6 + 915*x^4 - 2225*x^2 + 679, 1)
 

Normalized defining polynomial

\( x^{18} - 2 x^{16} + 57 x^{14} - 240 x^{12} + 1054 x^{10} - 2522 x^{8} + 2724 x^{6} + 915 x^{4} - 2225 x^{2} + 679 \)

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

Invariants

Degree:  $18$
magma: Degree(K);
 
sage: K.degree()
 
gp: poldegree(K.pol)
 
Signature:  $[0, 9]$
magma: Signature(K);
 
sage: K.signature()
 
gp: K.sign
 
Discriminant:  \(-30678065370140273522687719=-\,7^{9}\cdot 97^{9}\)
magma: Discriminant(Integers(K));
 
sage: K.disc()
 
gp: K.disc
 
Root discriminant:  $26.06$
magma: Abs(Discriminant(Integers(K)))^(1/Degree(K));
 
sage: (K.disc().abs())^(1./K.degree())
 
gp: abs(K.disc)^(1/poldegree(K.pol))
 
Ramified primes:  $7, 97$
magma: PrimeDivisors(Discriminant(Integers(K)));
 
sage: K.disc().support()
 
gp: factor(abs(K.disc))[,1]~
 
This field is Galois over $\Q$.
This is not a CM field.

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

$1$, $a$, $a^{2}$, $a^{3}$, $a^{4}$, $a^{5}$, $a^{6}$, $a^{7}$, $\frac{1}{3} a^{8} - \frac{1}{3}$, $\frac{1}{6} a^{9} - \frac{1}{2} a^{7} - \frac{1}{2} a^{2} - \frac{1}{6} a - \frac{1}{2}$, $\frac{1}{6} a^{10} - \frac{1}{6} a^{8} - \frac{1}{2} a^{3} - \frac{1}{6} a^{2} - \frac{1}{2} a - \frac{1}{3}$, $\frac{1}{6} a^{11} - \frac{1}{2} a^{7} - \frac{1}{2} a^{4} - \frac{1}{6} a^{3} - \frac{1}{2} a - \frac{1}{2}$, $\frac{1}{42} a^{12} - \frac{1}{14} a^{10} + \frac{1}{21} a^{8} + \frac{1}{7} a^{6} - \frac{1}{2} a^{5} + \frac{17}{42} a^{4} - \frac{1}{2} a^{3} + \frac{2}{7} a^{2} - \frac{1}{3}$, $\frac{1}{42} a^{13} - \frac{1}{14} a^{11} + \frac{1}{21} a^{9} + \frac{1}{7} a^{7} - \frac{1}{2} a^{6} + \frac{17}{42} a^{5} - \frac{1}{2} a^{4} + \frac{2}{7} a^{3} - \frac{1}{3} a$, $\frac{1}{42} a^{14} + \frac{5}{42} a^{8} - \frac{1}{2} a^{7} - \frac{1}{6} a^{6} - \frac{1}{2} a^{4} + \frac{5}{14} a^{2} - \frac{1}{2} a - \frac{1}{3}$, $\frac{1}{42} a^{15} - \frac{1}{21} a^{9} - \frac{1}{6} a^{8} + \frac{1}{3} a^{7} - \frac{1}{2} a^{5} + \frac{5}{14} a^{3} - \frac{1}{6} a + \frac{1}{6}$, $\frac{1}{383927173182} a^{16} - \frac{349793596}{63987862197} a^{14} - \frac{744788801}{127975724394} a^{12} + \frac{1354111921}{18282246342} a^{10} + \frac{11149632248}{191963586591} a^{8} - \frac{1}{2} a^{7} + \frac{21715821485}{127975724394} a^{6} - \frac{1}{2} a^{5} + \frac{16166130688}{63987862197} a^{4} - \frac{1}{2} a^{3} - \frac{14825407055}{63987862197} a^{2} - \frac{20997357983}{54846739026}$, $\frac{1}{383927173182} a^{17} - \frac{349793596}{63987862197} a^{15} - \frac{744788801}{127975724394} a^{13} + \frac{1354111921}{18282246342} a^{11} + \frac{11149632248}{191963586591} a^{9} - \frac{1}{6} a^{8} + \frac{21715821485}{127975724394} a^{7} - \frac{1}{2} a^{6} + \frac{16166130688}{63987862197} a^{5} - \frac{1}{2} a^{4} - \frac{14825407055}{63987862197} a^{3} - \frac{20997357983}{54846739026} a - \frac{1}{3}$

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

Class group and class number

$C_{2}$, which has order $2$

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

Unit group

magma: UK, f := UnitGroup(K);
 
sage: UK = K.unit_group()
 
Rank:  $8$
magma: UnitRank(K);
 
sage: UK.rank()
 
gp: K.fu
 
Torsion generator:  \( -1 \) (order $2$)
magma: K!f(TU.1) where TU,f is TorsionUnitGroup(K);
 
sage: UK.torsion_generator()
 
gp: K.tu[2]
 
Fundamental units:  Units are too long to display, but can be downloaded with other data for this field from 'Stored data to gp' link to the right
magma: [K!f(g): g in Generators(UK)];
 
sage: UK.fundamental_units()
 
gp: K.fu
 
Regulator:  \( 482397.970896 \)
magma: Regulator(K);
 
sage: K.regulator()
 
gp: K.reg
 

Galois group

$D_9$ (as 18T5):

magma: GaloisGroup(K);
 
sage: K.galois_group(type='pari')
 
gp: polgalois(K.pol)
 
A solvable group of order 18
The 6 conjugacy class representatives for $D_9$
Character table for $D_9$

Intermediate fields

\(\Q(\sqrt{-679}) \), 3.1.679.1 x3, 6.0.313046839.1, 9.1.212558803681.1 x9

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

Sibling fields

Degree 9 sibling: data not computed

Frobenius cycle types

$p$ 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59
Cycle type ${\href{/LocalNumberField/2.9.0.1}{9} }^{2}$ ${\href{/LocalNumberField/3.2.0.1}{2} }^{9}$ ${\href{/LocalNumberField/5.3.0.1}{3} }^{6}$ R ${\href{/LocalNumberField/11.9.0.1}{9} }^{2}$ ${\href{/LocalNumberField/13.9.0.1}{9} }^{2}$ ${\href{/LocalNumberField/17.9.0.1}{9} }^{2}$ ${\href{/LocalNumberField/19.9.0.1}{9} }^{2}$ ${\href{/LocalNumberField/23.2.0.1}{2} }^{9}$ ${\href{/LocalNumberField/29.2.0.1}{2} }^{9}$ ${\href{/LocalNumberField/31.2.0.1}{2} }^{9}$ ${\href{/LocalNumberField/37.2.0.1}{2} }^{9}$ ${\href{/LocalNumberField/41.9.0.1}{9} }^{2}$ ${\href{/LocalNumberField/43.9.0.1}{9} }^{2}$ ${\href{/LocalNumberField/47.2.0.1}{2} }^{9}$ ${\href{/LocalNumberField/53.9.0.1}{9} }^{2}$ ${\href{/LocalNumberField/59.9.0.1}{9} }^{2}$

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

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

Local algebras for ramified primes

$p$LabelPolynomial $e$ $f$ $c$ Galois group Slope content
$7$7.2.1.1$x^{2} - 7$$2$$1$$1$$C_2$$[\ ]_{2}$
7.2.1.1$x^{2} - 7$$2$$1$$1$$C_2$$[\ ]_{2}$
7.2.1.1$x^{2} - 7$$2$$1$$1$$C_2$$[\ ]_{2}$
7.2.1.1$x^{2} - 7$$2$$1$$1$$C_2$$[\ ]_{2}$
7.2.1.1$x^{2} - 7$$2$$1$$1$$C_2$$[\ ]_{2}$
7.2.1.1$x^{2} - 7$$2$$1$$1$$C_2$$[\ ]_{2}$
7.2.1.1$x^{2} - 7$$2$$1$$1$$C_2$$[\ ]_{2}$
7.2.1.1$x^{2} - 7$$2$$1$$1$$C_2$$[\ ]_{2}$
7.2.1.1$x^{2} - 7$$2$$1$$1$$C_2$$[\ ]_{2}$
$97$97.2.1.2$x^{2} + 485$$2$$1$$1$$C_2$$[\ ]_{2}$
97.2.1.2$x^{2} + 485$$2$$1$$1$$C_2$$[\ ]_{2}$
97.2.1.2$x^{2} + 485$$2$$1$$1$$C_2$$[\ ]_{2}$
97.2.1.2$x^{2} + 485$$2$$1$$1$$C_2$$[\ ]_{2}$
97.2.1.2$x^{2} + 485$$2$$1$$1$$C_2$$[\ ]_{2}$
97.2.1.2$x^{2} + 485$$2$$1$$1$$C_2$$[\ ]_{2}$
97.2.1.2$x^{2} + 485$$2$$1$$1$$C_2$$[\ ]_{2}$
97.2.1.2$x^{2} + 485$$2$$1$$1$$C_2$$[\ ]_{2}$
97.2.1.2$x^{2} + 485$$2$$1$$1$$C_2$$[\ ]_{2}$