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Properties

Label 8.2.17256481947.2
Degree $8$
Signature $[2, 3]$
Discriminant $-\,3^{7}\cdot 53^{4}$
Root discriminant $19.04$
Ramified primes $3, 53$
Class number $3$
Class group $[3]$
Galois group $\textrm{GL(2,3)}$ (as 8T23)

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Show commands for: Magma / SageMath / Pari/GP

magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![-3, 12, -21, 21, -15, 9, 0, -3, 1]);
 
sage: x = polygen(QQ); K.<a> = NumberField(x^8 - 3*x^7 + 9*x^5 - 15*x^4 + 21*x^3 - 21*x^2 + 12*x - 3)
 
gp: K = bnfinit(x^8 - 3*x^7 + 9*x^5 - 15*x^4 + 21*x^3 - 21*x^2 + 12*x - 3, 1)
 

Normalized defining polynomial

\( x^{8} - 3 x^{7} + 9 x^{5} - 15 x^{4} + 21 x^{3} - 21 x^{2} + 12 x - 3 \)

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

Invariants

Degree:  $8$
magma: Degree(K);
 
sage: K.degree()
 
gp: poldegree(K.pol)
 
Signature:  $[2, 3]$
magma: Signature(K);
 
sage: K.signature()
 
gp: K.sign
 
Discriminant:  \(-17256481947=-\,3^{7}\cdot 53^{4}\)
magma: Discriminant(Integers(K));
 
sage: K.disc()
 
gp: K.disc
 
Root discriminant:  $19.04$
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:  $3, 53$
magma: PrimeDivisors(Discriminant(Integers(K)));
 
sage: K.disc().support()
 
gp: factor(abs(K.disc))[,1]~
 
This field is not Galois over $\Q$.
This is not a CM field.

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

$1$, $a$, $a^{2}$, $a^{3}$, $a^{4}$, $a^{5}$, $a^{6}$, $\frac{1}{5} a^{7} - \frac{1}{5} a^{6} - \frac{2}{5} a^{5} + \frac{1}{5} a^{2} + \frac{1}{5} a - \frac{1}{5}$

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

Class group and class number

$C_{3}$, which has order $3$

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

Unit group

magma: UK, f := UnitGroup(K);
 
sage: UK = K.unit_group()
 
Rank:  $4$
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:  \( a - 1 \),  \( \frac{4}{5} a^{7} - \frac{4}{5} a^{6} - \frac{18}{5} a^{5} + 4 a^{4} + a^{3} + \frac{19}{5} a^{2} + \frac{19}{5} a - \frac{29}{5} \),  \( \frac{8}{5} a^{7} - \frac{28}{5} a^{6} + \frac{4}{5} a^{5} + 18 a^{4} - 28 a^{3} + \frac{163}{5} a^{2} - \frac{187}{5} a + \frac{82}{5} \),  \( \frac{12}{5} a^{7} - \frac{32}{5} a^{6} - \frac{14}{5} a^{5} + 22 a^{4} - 27 a^{3} + \frac{182}{5} a^{2} - \frac{168}{5} a + \frac{53}{5} \)
magma: [K!f(g): g in Generators(UK)];
 
sage: UK.fundamental_units()
 
gp: K.fu
 
Regulator:  \( 62.5978134234 \)
magma: Regulator(K);
 
sage: K.regulator()
 
gp: K.reg
 

Galois group

$\GL(2,3)$ (as 8T23):

magma: GaloisGroup(K);
 
sage: K.galois_group(type='pari')
 
gp: polgalois(K.pol)
 
A solvable group of order 48
The 8 conjugacy class representatives for $\textrm{GL(2,3)}$
Character table for $\textrm{GL(2,3)}$

Intermediate fields

4.2.75843.1

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

Sibling fields

Degree 16 sibling: data not computed
Degree 24 sibling: data not computed
Arithmetically equvalently sibling: 8.2.17256481947.1

Frobenius cycle types

$p$ 2 3 5 7 11 13 17 19 23 29 31 37 41 43 47 53 59
Cycle type ${\href{/LocalNumberField/2.8.0.1}{8} }$ R ${\href{/LocalNumberField/5.2.0.1}{2} }^{3}{,}\,{\href{/LocalNumberField/5.1.0.1}{1} }^{2}$ ${\href{/LocalNumberField/7.3.0.1}{3} }^{2}{,}\,{\href{/LocalNumberField/7.1.0.1}{1} }^{2}$ ${\href{/LocalNumberField/11.2.0.1}{2} }^{3}{,}\,{\href{/LocalNumberField/11.1.0.1}{1} }^{2}$ ${\href{/LocalNumberField/13.4.0.1}{4} }^{2}$ ${\href{/LocalNumberField/17.2.0.1}{2} }^{3}{,}\,{\href{/LocalNumberField/17.1.0.1}{1} }^{2}$ ${\href{/LocalNumberField/19.6.0.1}{6} }{,}\,{\href{/LocalNumberField/19.2.0.1}{2} }$ ${\href{/LocalNumberField/23.8.0.1}{8} }$ ${\href{/LocalNumberField/29.8.0.1}{8} }$ ${\href{/LocalNumberField/31.6.0.1}{6} }{,}\,{\href{/LocalNumberField/31.2.0.1}{2} }$ ${\href{/LocalNumberField/37.3.0.1}{3} }^{2}{,}\,{\href{/LocalNumberField/37.1.0.1}{1} }^{2}$ ${\href{/LocalNumberField/41.2.0.1}{2} }^{3}{,}\,{\href{/LocalNumberField/41.1.0.1}{1} }^{2}$ ${\href{/LocalNumberField/43.6.0.1}{6} }{,}\,{\href{/LocalNumberField/43.2.0.1}{2} }$ ${\href{/LocalNumberField/47.8.0.1}{8} }$ R ${\href{/LocalNumberField/59.8.0.1}{8} }$

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
$3$3.8.7.2$x^{8} - 3$$8$$1$$7$$QD_{16}$$[\ ]_{8}^{2}$
$53$53.2.0.1$x^{2} - x + 5$$1$$2$$0$$C_2$$[\ ]^{2}$
53.3.2.1$x^{3} - 53$$3$$1$$2$$S_3$$[\ ]_{3}^{2}$
53.3.2.1$x^{3} - 53$$3$$1$$2$$S_3$$[\ ]_{3}^{2}$

Artin representations

Label Dimension Conductor Defining polynomial of Artin field $G$ Ind $\chi(c)$
* 1.1.1t1.1c1$1$ $1$ $x$ $C_1$ $1$ $1$
1.3.2t1.1c1$1$ $ 3 $ $x^{2} - x + 1$ $C_2$ (as 2T1) $1$ $-1$
2.3_53e2.3t2.1c1$2$ $ 3 \cdot 53^{2}$ $x^{3} - 53$ $S_3$ (as 3T2) $1$ $0$
2.3e2_53e2.24t22.2c1$2$ $ 3^{2} \cdot 53^{2}$ $x^{8} - 3 x^{7} + 9 x^{5} - 15 x^{4} + 21 x^{3} - 21 x^{2} + 12 x - 3$ $\textrm{GL(2,3)}$ (as 8T23) $0$ $0$
2.3e2_53e2.24t22.2c2$2$ $ 3^{2} \cdot 53^{2}$ $x^{8} - 3 x^{7} + 9 x^{5} - 15 x^{4} + 21 x^{3} - 21 x^{2} + 12 x - 3$ $\textrm{GL(2,3)}$ (as 8T23) $0$ $0$
3.3e2_53e2.6t8.1c1$3$ $ 3^{2} \cdot 53^{2}$ $x^{4} - x^{3} - 6 x^{2} + 8 x - 5$ $S_4$ (as 4T5) $1$ $-1$
* 3.3e3_53e2.4t5.1c1$3$ $ 3^{3} \cdot 53^{2}$ $x^{4} - x^{3} - 6 x^{2} + 8 x - 5$ $S_4$ (as 4T5) $1$ $1$
* 4.3e4_53e2.8t23.2c1$4$ $ 3^{4} \cdot 53^{2}$ $x^{8} - 3 x^{7} + 9 x^{5} - 15 x^{4} + 21 x^{3} - 21 x^{2} + 12 x - 3$ $\textrm{GL(2,3)}$ (as 8T23) $1$ $0$

Data is given for all irreducible representations of the Galois group for the Galois closure of this field. Those marked with * are summands in the permutation representation coming from this field. Representations which appear with multiplicity greater than one are indicated by exponents on the *.