magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![3, -16, 40, -56, 38, -8, 0, 0, 1]);
sage: x = polygen(QQ); K.<a> = NumberField(x^8 - 8*x^5 + 38*x^4 - 56*x^3 + 40*x^2 - 16*x + 3)
gp: K = bnfinit(x^8 - 8*x^5 + 38*x^4 - 56*x^3 + 40*x^2 - 16*x + 3, 1)
Normalized defining polynomial
\( x^{8} - 8 x^{5} + 38 x^{4} - 56 x^{3} + 40 x^{2} - 16 x + 3 \)
magma: DefiningPolynomial(K);
sage: K.defining_polynomial()
gp: K.pol
Invariants
| Degree: | $8$ | magma: Degree(K);
sage: K.degree()
gp: poldegree(K.pol)
| |
| Signature: | $[0, 4]$ | magma: Signature(K);
sage: K.signature()
gp: K.sign
| |
| Discriminant: | \(41943040000=2^{26}\cdot 5^{4}\) | magma: Discriminant(Integers(K));
sage: K.disc()
gp: K.disc
| |
| Root discriminant: | $21.27$ | 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: | $2, 5$ | 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 \(a\))
$1$, $a$, $a^{2}$, $a^{3}$, $a^{4}$, $a^{5}$, $a^{6}$, $\frac{1}{17} a^{7} - \frac{7}{17} a^{6} - \frac{2}{17} a^{5} + \frac{6}{17} a^{4} - \frac{4}{17} a^{3} + \frac{6}{17} a^{2} - \frac{2}{17} a - \frac{2}{17}$
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: | $3$ | 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: | \( 161.602330591 \) | magma: Regulator(K);
sage: K.regulator()
gp: K.reg
|
Galois group
$C_2^2:S_4$ (as 8T34):
magma: GaloisGroup(K);
sage: K.galois_group(type='pari')
gp: polgalois(K.pol)
| A solvable group of order 96 |
| The 10 conjugacy class representatives for $V_4^2:S_3$ |
| Character table for $V_4^2:S_3$ |
Intermediate fields
| \(\Q(\sqrt{-2}) \) |
Fields in the database are given up to isomorphism. Isomorphic intermediate fields are shown with their multiplicities.
Sibling fields
| Degree 12 siblings: | data not computed |
| Degree 16 sibling: | data not computed |
| Degree 24 siblings: | data not computed |
| Degree 32 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 | R | ${\href{/LocalNumberField/3.3.0.1}{3} }^{2}{,}\,{\href{/LocalNumberField/3.1.0.1}{1} }^{2}$ | R | ${\href{/LocalNumberField/7.4.0.1}{4} }^{2}$ | ${\href{/LocalNumberField/11.3.0.1}{3} }^{2}{,}\,{\href{/LocalNumberField/11.1.0.1}{1} }^{2}$ | ${\href{/LocalNumberField/13.4.0.1}{4} }^{2}$ | ${\href{/LocalNumberField/17.3.0.1}{3} }^{2}{,}\,{\href{/LocalNumberField/17.1.0.1}{1} }^{2}$ | ${\href{/LocalNumberField/19.3.0.1}{3} }^{2}{,}\,{\href{/LocalNumberField/19.1.0.1}{1} }^{2}$ | ${\href{/LocalNumberField/23.4.0.1}{4} }^{2}$ | ${\href{/LocalNumberField/29.4.0.1}{4} }^{2}$ | ${\href{/LocalNumberField/31.4.0.1}{4} }^{2}$ | ${\href{/LocalNumberField/37.4.0.1}{4} }^{2}$ | ${\href{/LocalNumberField/41.3.0.1}{3} }^{2}{,}\,{\href{/LocalNumberField/41.1.0.1}{1} }^{2}$ | ${\href{/LocalNumberField/43.2.0.1}{2} }^{2}{,}\,{\href{/LocalNumberField/43.1.0.1}{1} }^{4}$ | ${\href{/LocalNumberField/47.4.0.1}{4} }^{2}$ | ${\href{/LocalNumberField/53.4.0.1}{4} }^{2}$ | ${\href{/LocalNumberField/59.2.0.1}{2} }^{4}$ |
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
| $p$ | Label | Polynomial | $e$ | $f$ | $c$ | Galois group | Slope content |
|---|---|---|---|---|---|---|---|
| $2$ | 2.8.26.31 | $x^{8} + 8 x^{7} + 4 x^{6} + 8 x^{4} + 8 x^{3} + 8 x^{2} + 22$ | $8$ | $1$ | $26$ | $C_2^2 \wr C_2$ | $[2, 3, 7/2, 4]^{2}$ |
| $5$ | 5.2.0.1 | $x^{2} - x + 2$ | $1$ | $2$ | $0$ | $C_2$ | $[\ ]^{2}$ |
| 5.6.4.1 | $x^{6} + 25 x^{3} + 200$ | $3$ | $2$ | $4$ | $S_3$ | $[\ ]_{3}^{2}$ |
Artin representations
| Label | Dimension | Conductor | Defining polynomial of Artin field | $G$ | Ind | $\chi(c)$ | |
|---|---|---|---|---|---|---|---|
| * | 1.1.1t1.1c1 | $1$ | $1$ | $x$ | $C_1$ | $1$ | $1$ |
| * | 1.2e3.2t1.2c1 | $1$ | $ 2^{3}$ | $x^{2} + 2$ | $C_2$ (as 2T1) | $1$ | $-1$ |
| 2.2e3_5e2.3t2.1c1 | $2$ | $ 2^{3} \cdot 5^{2}$ | $x^{3} - x^{2} + 2 x + 2$ | $S_3$ (as 3T2) | $1$ | $0$ | |
| 3.2e11_5e2.4t5.1c1 | $3$ | $ 2^{11} \cdot 5^{2}$ | $x^{4} - 4 x^{2} - 16 x - 18$ | $S_4$ (as 4T5) | $1$ | $1$ | |
| 3.2e11_5e2.4t5.2c1 | $3$ | $ 2^{11} \cdot 5^{2}$ | $x^{4} + 4 x^{2} - 8 x + 2$ | $S_4$ (as 4T5) | $1$ | $1$ | |
| 3.2e9_5e2.4t5.1c1 | $3$ | $ 2^{9} \cdot 5^{2}$ | $x^{4} - 4 x^{2} - 4 x - 3$ | $S_4$ (as 4T5) | $1$ | $1$ | |
| 3.2e8_5e2.6t8.1c1 | $3$ | $ 2^{8} \cdot 5^{2}$ | $x^{4} - 4 x^{2} - 16 x - 18$ | $S_4$ (as 4T5) | $1$ | $-1$ | |
| 3.2e10_5e2.6t8.1c1 | $3$ | $ 2^{10} \cdot 5^{2}$ | $x^{4} - 4 x^{2} - 4 x - 3$ | $S_4$ (as 4T5) | $1$ | $-1$ | |
| 3.2e10_5e2.6t8.2c1 | $3$ | $ 2^{10} \cdot 5^{2}$ | $x^{4} + 4 x^{2} - 8 x + 2$ | $S_4$ (as 4T5) | $1$ | $-1$ | |
| * | 6.2e23_5e4.8t34.1c1 | $6$ | $ 2^{23} \cdot 5^{4}$ | $x^{8} - 8 x^{5} + 38 x^{4} - 56 x^{3} + 40 x^{2} - 16 x + 3$ | $V_4^2:S_3$ (as 8T34) | $1$ | $0$ |
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 *.