magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![7, -21, 30, -34, 28, -15, 10, -2, 1]);
sage: x = polygen(QQ); K.<a> = NumberField(x^8 - 2*x^7 + 10*x^6 - 15*x^5 + 28*x^4 - 34*x^3 + 30*x^2 - 21*x + 7)
gp: K = bnfinit(x^8 - 2*x^7 + 10*x^6 - 15*x^5 + 28*x^4 - 34*x^3 + 30*x^2 - 21*x + 7, 1)
Normalized defining polynomial
\( x^{8} - 2 x^{7} + 10 x^{6} - 15 x^{5} + 28 x^{4} - 34 x^{3} + 30 x^{2} - 21 x + 7 \)
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: | \(311169600=2^{6}\cdot 3^{4}\cdot 5^{2}\cdot 7^{4}\) | magma: Discriminant(Integers(K));
sage: K.disc()
gp: K.disc
| |
| Root discriminant: | $11.52$ | 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: | $2, 3, 5, 7$ | 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 \(a\))
$1$, $a$, $a^{2}$, $a^{3}$, $a^{4}$, $a^{5}$, $\frac{1}{2} a^{6} - \frac{1}{2} a^{4} - \frac{1}{2} a^{3} - \frac{1}{2} a^{2} - \frac{1}{2} a - \frac{1}{2}$, $\frac{1}{86} a^{7} + \frac{1}{86} a^{6} + \frac{13}{86} a^{5} + \frac{12}{43} a^{4} + \frac{7}{43} a^{3} + \frac{4}{43} a^{2} - \frac{16}{43} a - \frac{31}{86}$
magma: IntegralBasis(K);
sage: K.integral_basis()
gp: K.zk
Class group and class number
Trivial group, which has order $1$
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: | \( \frac{21}{86} a^{7} - \frac{11}{43} a^{6} + \frac{187}{86} a^{5} - \frac{141}{86} a^{4} + \frac{423}{86} a^{3} - \frac{305}{86} a^{2} + \frac{231}{86} a - \frac{46}{43} \) (order $6$) | 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: | \( 25.8517489962 \) | magma: Regulator(K);
sage: K.regulator()
gp: K.reg
|
Galois group
$Q_8:C_2^2$ (as 8T22):
magma: GaloisGroup(K);
sage: K.galois_group(type='pari')
gp: polgalois(K.pol)
| A solvable group of order 32 |
| The 17 conjugacy class representatives for $C_2^3 : D_4 $ |
| Character table for $C_2^3 : D_4 $ |
Intermediate fields
| \(\Q(\sqrt{-3}) \), \(\Q(\sqrt{-7}) \), \(\Q(\sqrt{21}) \), \(\Q(\sqrt{-3}, \sqrt{-7})\) |
Fields in the database are given up to isomorphism. Isomorphic intermediate fields are shown with their multiplicities.
Sibling fields
| Galois closure: | data not computed |
| Degree 8 siblings: | data not computed |
| Degree 16 siblings: | 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 | R | R | R | ${\href{/LocalNumberField/11.2.0.1}{2} }^{4}$ | ${\href{/LocalNumberField/13.2.0.1}{2} }^{4}$ | ${\href{/LocalNumberField/17.4.0.1}{4} }^{2}$ | ${\href{/LocalNumberField/19.2.0.1}{2} }^{4}$ | ${\href{/LocalNumberField/23.4.0.1}{4} }^{2}$ | ${\href{/LocalNumberField/29.2.0.1}{2} }^{4}$ | ${\href{/LocalNumberField/31.4.0.1}{4} }^{2}$ | ${\href{/LocalNumberField/37.2.0.1}{2} }^{2}{,}\,{\href{/LocalNumberField/37.1.0.1}{1} }^{4}$ | ${\href{/LocalNumberField/41.4.0.1}{4} }^{2}$ | ${\href{/LocalNumberField/43.2.0.1}{2} }^{2}{,}\,{\href{/LocalNumberField/43.1.0.1}{1} }^{4}$ | ${\href{/LocalNumberField/47.2.0.1}{2} }^{4}$ | ${\href{/LocalNumberField/53.4.0.1}{4} }^{2}$ | ${\href{/LocalNumberField/59.4.0.1}{4} }^{2}$ |
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
| $p$ | Label | Polynomial | $e$ | $f$ | $c$ | Galois group | Slope content |
|---|---|---|---|---|---|---|---|
| $2$ | 2.4.6.4 | $x^{4} - 2 x^{2} + 20$ | $2$ | $2$ | $6$ | $C_4$ | $[3]^{2}$ |
| 2.4.0.1 | $x^{4} - x + 1$ | $1$ | $4$ | $0$ | $C_4$ | $[\ ]^{4}$ | |
| $3$ | 3.8.4.1 | $x^{8} + 36 x^{4} - 27 x^{2} + 324$ | $2$ | $4$ | $4$ | $C_4\times C_2$ | $[\ ]_{2}^{4}$ |
| $5$ | 5.2.0.1 | $x^{2} - x + 2$ | $1$ | $2$ | $0$ | $C_2$ | $[\ ]^{2}$ |
| 5.2.0.1 | $x^{2} - x + 2$ | $1$ | $2$ | $0$ | $C_2$ | $[\ ]^{2}$ | |
| 5.4.2.1 | $x^{4} + 15 x^{2} + 100$ | $2$ | $2$ | $2$ | $C_2^2$ | $[\ ]_{2}^{2}$ | |
| $7$ | 7.2.1.2 | $x^{2} + 14$ | $2$ | $1$ | $1$ | $C_2$ | $[\ ]_{2}$ |
| 7.2.1.2 | $x^{2} + 14$ | $2$ | $1$ | $1$ | $C_2$ | $[\ ]_{2}$ | |
| 7.4.2.1 | $x^{4} + 35 x^{2} + 441$ | $2$ | $2$ | $2$ | $C_2^2$ | $[\ ]_{2}^{2}$ |
Artin representations
| Label | Dimension | Conductor | Defining polynomial of Artin field | $G$ | Ind | $\chi(c)$ | |
|---|---|---|---|---|---|---|---|
| * | 1.1.1t1.1c1 | $1$ | $1$ | $x$ | $C_1$ | $1$ | $1$ |
| 1.5_7.2t1.1c1 | $1$ | $ 5 \cdot 7 $ | $x^{2} - x + 9$ | $C_2$ (as 2T1) | $1$ | $-1$ | |
| 1.2e3_7.2t1.1c1 | $1$ | $ 2^{3} \cdot 7 $ | $x^{2} - 14$ | $C_2$ (as 2T1) | $1$ | $1$ | |
| 1.2e3_5.2t1.2c1 | $1$ | $ 2^{3} \cdot 5 $ | $x^{2} + 10$ | $C_2$ (as 2T1) | $1$ | $-1$ | |
| 1.3_5.2t1.1c1 | $1$ | $ 3 \cdot 5 $ | $x^{2} - x + 4$ | $C_2$ (as 2T1) | $1$ | $-1$ | |
| 1.2e3_3.2t1.1c1 | $1$ | $ 2^{3} \cdot 3 $ | $x^{2} - 6$ | $C_2$ (as 2T1) | $1$ | $1$ | |
| * | 1.3_7.2t1.1c1 | $1$ | $ 3 \cdot 7 $ | $x^{2} - x - 5$ | $C_2$ (as 2T1) | $1$ | $1$ |
| 1.2e3_3_5_7.2t1.2c1 | $1$ | $ 2^{3} \cdot 3 \cdot 5 \cdot 7 $ | $x^{2} + 210$ | $C_2$ (as 2T1) | $1$ | $-1$ | |
| 1.2e3_3_7.2t1.2c1 | $1$ | $ 2^{3} \cdot 3 \cdot 7 $ | $x^{2} + 42$ | $C_2$ (as 2T1) | $1$ | $-1$ | |
| 1.3_5_7.2t1.1c1 | $1$ | $ 3 \cdot 5 \cdot 7 $ | $x^{2} - x - 26$ | $C_2$ (as 2T1) | $1$ | $1$ | |
| 1.2e3_3_5.2t1.1c1 | $1$ | $ 2^{3} \cdot 3 \cdot 5 $ | $x^{2} - 30$ | $C_2$ (as 2T1) | $1$ | $1$ | |
| * | 1.3.2t1.1c1 | $1$ | $ 3 $ | $x^{2} - x + 1$ | $C_2$ (as 2T1) | $1$ | $-1$ |
| 1.2e3.2t1.2c1 | $1$ | $ 2^{3}$ | $x^{2} + 2$ | $C_2$ (as 2T1) | $1$ | $-1$ | |
| 1.5.2t1.1c1 | $1$ | $ 5 $ | $x^{2} - x - 1$ | $C_2$ (as 2T1) | $1$ | $1$ | |
| 1.2e3_5_7.2t1.1c1 | $1$ | $ 2^{3} \cdot 5 \cdot 7 $ | $x^{2} - 70$ | $C_2$ (as 2T1) | $1$ | $1$ | |
| * | 1.7.2t1.1c1 | $1$ | $ 7 $ | $x^{2} - x + 2$ | $C_2$ (as 2T1) | $1$ | $-1$ |
| * | 4.2e6_3e2_5e2_7e2.8t22.10c1 | $4$ | $ 2^{6} \cdot 3^{2} \cdot 5^{2} \cdot 7^{2}$ | $x^{8} - 2 x^{7} + 10 x^{6} - 15 x^{5} + 28 x^{4} - 34 x^{3} + 30 x^{2} - 21 x + 7$ | $C_2^3 : D_4 $ (as 8T22) | $1$ | $0$ |
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 *.