# Properties

 Label 4.2.8619.2 Degree $4$ Signature $[2, 1]$ Discriminant $-8619$ Root discriminant $9.64$ Ramified primes $3, 13, 17$ Class number $1$ Class group trivial Galois group $D_{4}$ (as 4T3)

# Related objects

Show commands: SageMath / Pari/GP / Magma

## Normalizeddefining polynomial

sage: x = polygen(QQ); K.<a> = NumberField(x^4 - 2*x^3 + 2*x^2 - x - 3)

gp: K = bnfinit(x^4 - 2*x^3 + 2*x^2 - x - 3, 1)

magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![-3, -1, 2, -2, 1]);

$$x^{4} - 2 x^{3} + 2 x^{2} - x - 3$$

sage: K.defining_polynomial()

gp: K.pol

magma: DefiningPolynomial(K);

## Invariants

 Degree: $4$ sage: K.degree()  gp: poldegree(K.pol)  magma: Degree(K); Signature: $[2, 1]$ sage: K.signature()  gp: K.sign  magma: Signature(K); Discriminant: $$-8619$$$$\medspace = -\,3\cdot 13^{2}\cdot 17$$ sage: K.disc()  gp: K.disc  magma: Discriminant(Integers(K)); Root discriminant: $9.64$ sage: (K.disc().abs())^(1./K.degree())  gp: abs(K.disc)^(1/poldegree(K.pol))  magma: Abs(Discriminant(Integers(K)))^(1/Degree(K)); Ramified primes: $3, 13, 17$ sage: K.disc().support()  gp: factor(abs(K.disc))[,1]~  magma: PrimeDivisors(Discriminant(Integers(K))); $|\Aut(K/\Q)|$: $2$ This field is not Galois over $\Q$. This is not a CM field.

## Integral basis (with respect to field generator $$a$$)

$1$, $a$, $a^{2}$, $a^{3}$

sage: K.integral_basis()

gp: K.zk

magma: IntegralBasis(K);

## Class group and class number

Trivial group, which has order $1$

sage: K.class_group().invariants()

gp: K.clgp

magma: ClassGroup(K);

## Unit group

sage: UK = K.unit_group()

magma: UK, f := UnitGroup(K);

 Rank: $2$ sage: UK.rank()  gp: K.fu  magma: UnitRank(K); Torsion generator: $$-1$$ (order $2$) sage: UK.torsion_generator()  gp: K.tu[2]  magma: K!f(TU.1) where TU,f is TorsionUnitGroup(K); Fundamental units: $$a^{2} - a - 1$$,  $$a^{3} + 2 a + 2$$ sage: UK.fundamental_units()  gp: K.fu  magma: [K!f(g): g in Generators(UK)]; Regulator: $$5.6894971291$$ sage: K.regulator()  gp: K.reg  magma: Regulator(K);

## Class number formula

$\displaystyle\lim_{s\to 1} (s-1)\zeta_K(s) \approx\frac{2^{2}\cdot(2\pi)^{1}\cdot 5.6894971291 \cdot 1}{2\sqrt{8619}}\approx 0.77011451021$

## Galois group

$D_4$ (as 4T3):

sage: K.galois_group(type='pari')

gp: polgalois(K.pol)

magma: GaloisGroup(K);

 A solvable group of order 8 The 5 conjugacy class representatives for $D_{4}$ Character table for $D_{4}$

## Intermediate fields

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

## Sibling fields

 Galois closure: 8.0.193220905761.3 Degree 4 sibling: 4.0.33813.1

## Frobenius cycle types

 $p$ $2$ $3$ $5$ $7$ $11$ $13$ $17$ $19$ $23$ $29$ $31$ $37$ $41$ $43$ $47$ $53$ $59$ Cycle type ${\href{/padicField/2.4.0.1}{4} }$ R ${\href{/padicField/5.2.0.1}{2} }^{2}$ ${\href{/padicField/7.4.0.1}{4} }$ ${\href{/padicField/11.2.0.1}{2} }^{2}$ R R ${\href{/padicField/19.2.0.1}{2} }^{2}$ ${\href{/padicField/23.2.0.1}{2} }^{2}$ ${\href{/padicField/29.2.0.1}{2} }^{2}$ ${\href{/padicField/31.4.0.1}{4} }$ ${\href{/padicField/37.4.0.1}{4} }$ ${\href{/padicField/41.2.0.1}{2} }^{2}$ ${\href{/padicField/43.2.0.1}{2} }^{2}$ ${\href{/padicField/47.4.0.1}{4} }$ ${\href{/padicField/53.2.0.1}{2} }{,}\,{\href{/padicField/53.1.0.1}{1} }^{2}$ ${\href{/padicField/59.4.0.1}{4} }$

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

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]])

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];

## Local algebras for ramified primes

$p$LabelPolynomial $e$ $f$ $c$ Galois group Slope content
$3$$\Q_{3}$$x + 1$$1$$1$$0Trivial[\ ] \Q_{3}$$x + 1$$1$$1$$0Trivial[\ ] 3.2.1.1x^{2} - 3$$2$$1$$1$$C_2$$[\ ]_{2}$
$13$13.2.1.1$x^{2} - 13$$2$$1$$1$$C_2$$[\ ]_{2} 13.2.1.1x^{2} - 13$$2$$1$$1$$C_2$$[\ ]_{2}$
$17$$\Q_{17}$$x + 3$$1$$1$$0Trivial[\ ] \Q_{17}$$x + 3$$1$$1$$0Trivial[\ ] 17.2.1.2x^{2} + 51$$2$$1$$1$$C_2$$[\ ]_{2}$

## Artin representations

Label Dimension Conductor Artin stem field $G$ Ind $\chi(c)$
* 1.1.1t1.a.a$1$ $1$ $$\Q$$ $C_1$ $1$ $1$
* 1.13.2t1.a.a$1$ $13$ $$\Q(\sqrt{13})$$ $C_2$ (as 2T1) $1$ $1$
1.51.2t1.a.a$1$ $3 \cdot 17$ $$\Q(\sqrt{-51})$$ $C_2$ (as 2T1) $1$ $-1$
1.663.2t1.a.a$1$ $3 \cdot 13 \cdot 17$ $$\Q(\sqrt{-663})$$ $C_2$ (as 2T1) $1$ $-1$
* 2.663.4t3.b.a$2$ $3 \cdot 13 \cdot 17$ 4.2.8619.2 $D_{4}$ (as 4T3) $1$ $0$

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 *.