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Properties

Label 21.1.88650872221...2304.1
Degree $21$
Signature $[1, 10]$
Discriminant $2^{14}\cdot 3^{24}\cdot 7^{24}$
Root discriminant $51.50$
Ramified primes $2, 3, 7$
Class number $1$ (GRH)
Class group Trivial (GRH)
Galois group $D_{21}:C_3$ (as 21T10)

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Show commands for: Magma / SageMath / Pari/GP

magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(R![-1024, 0, 0, -4928, 0, 0, -7840, 0, 0, -4480, 0, 0, -392, 0, 0, 672, 0, 0, -42, 0, 0, 1]);
 
sage: x = polygen(QQ); K.<a> = NumberField(x^21 - 42*x^18 + 672*x^15 - 392*x^12 - 4480*x^9 - 7840*x^6 - 4928*x^3 - 1024)
 
gp: K = bnfinit(x^21 - 42*x^18 + 672*x^15 - 392*x^12 - 4480*x^9 - 7840*x^6 - 4928*x^3 - 1024, 1)
 

Normalized defining polynomial

\( x^{21} - 42 x^{18} + 672 x^{15} - 392 x^{12} - 4480 x^{9} - 7840 x^{6} - 4928 x^{3} - 1024 \)

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

Invariants

Degree:  $21$
magma: Degree(K);
 
sage: K.degree()
 
gp: poldegree(K.pol)
 
Signature:  $[1, 10]$
magma: Signature(K);
 
sage: K.signature()
 
gp: K.sign
 
Discriminant:  \(886508722213234018394285560019042304=2^{14}\cdot 3^{24}\cdot 7^{24}\)
magma: Discriminant(Integers(K));
 
sage: K.disc()
 
gp: K.disc
 
Root discriminant:  $51.50$
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:  $2, 3, 7$
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 \(a\))

$1$, $a$, $a^{2}$, $\frac{1}{2} a^{3}$, $\frac{1}{2} a^{4}$, $\frac{1}{2} a^{5}$, $\frac{1}{4} a^{6}$, $\frac{1}{8} a^{7} - \frac{1}{4} a^{4} - \frac{1}{2} a$, $\frac{1}{8} a^{8} - \frac{1}{4} a^{5} - \frac{1}{2} a^{2}$, $\frac{1}{16} a^{9} - \frac{1}{8} a^{6} - \frac{1}{4} a^{3}$, $\frac{1}{16} a^{10} - \frac{1}{2} a$, $\frac{1}{16} a^{11} - \frac{1}{2} a^{2}$, $\frac{1}{288} a^{12} - \frac{1}{144} a^{9} + \frac{1}{72} a^{6} + \frac{1}{18} a^{3} + \frac{4}{9}$, $\frac{1}{288} a^{13} - \frac{1}{144} a^{10} + \frac{1}{72} a^{7} + \frac{1}{18} a^{4} + \frac{4}{9} a$, $\frac{1}{576} a^{14} + \frac{1}{36} a^{11} + \frac{1}{144} a^{8} - \frac{2}{9} a^{5} + \frac{17}{36} a^{2}$, $\frac{1}{1152} a^{15} - \frac{1}{32} a^{9} - \frac{1}{24} a^{6} - \frac{17}{72} a^{3} + \frac{2}{9}$, $\frac{1}{1152} a^{16} - \frac{1}{32} a^{10} - \frac{1}{24} a^{7} - \frac{17}{72} a^{4} + \frac{2}{9} a$, $\frac{1}{1152} a^{17} - \frac{1}{32} a^{11} - \frac{1}{24} a^{8} - \frac{17}{72} a^{5} + \frac{2}{9} a^{2}$, $\frac{1}{960768} a^{18} - \frac{1}{3456} a^{17} - \frac{1}{3456} a^{16} - \frac{17}{40032} a^{15} - \frac{1}{1728} a^{14} - \frac{1}{864} a^{13} + \frac{109}{240192} a^{12} + \frac{19}{864} a^{11} - \frac{25}{864} a^{10} + \frac{1261}{60048} a^{9} - \frac{13}{432} a^{8} + \frac{1}{108} a^{7} + \frac{2315}{60048} a^{6} + \frac{17}{72} a^{5} + \frac{13}{216} a^{4} - \frac{3445}{15012} a^{3} - \frac{25}{108} a^{2} + \frac{1}{9} a - \frac{1270}{3753}$, $\frac{1}{960768} a^{19} - \frac{65}{480384} a^{16} + \frac{1}{3456} a^{15} - \frac{1}{1728} a^{14} + \frac{43}{26688} a^{13} - \frac{1}{864} a^{12} + \frac{5}{432} a^{11} - \frac{503}{40032} a^{10} + \frac{11}{864} a^{9} + \frac{17}{432} a^{8} + \frac{1759}{60048} a^{7} + \frac{5}{216} a^{6} - \frac{19}{108} a^{5} + \frac{2105}{10008} a^{4} - \frac{1}{72} a^{3} - \frac{17}{108} a^{2} + \frac{379}{7506} a + \frac{7}{27}$, $\frac{1}{960768} a^{20} - \frac{65}{480384} a^{17} + \frac{1}{3456} a^{16} + \frac{1}{3456} a^{15} - \frac{5}{40032} a^{14} - \frac{1}{864} a^{13} + \frac{1}{864} a^{12} + \frac{887}{40032} a^{11} + \frac{11}{864} a^{10} + \frac{25}{864} a^{9} + \frac{671}{30024} a^{8} + \frac{5}{216} a^{7} - \frac{1}{108} a^{6} - \frac{75}{1112} a^{5} - \frac{1}{72} a^{4} - \frac{13}{216} a^{3} + \frac{1175}{15012} a^{2} + \frac{7}{27} a - \frac{1}{9}$

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

Class group and class number

Trivial group, which has order $1$ (assuming GRH)

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

Unit group

magma: UK, f := UnitGroup(K);
 
sage: UK = K.unit_group()
 
Rank:  $10$
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 (assuming GRH)
magma: [K!f(g): g in Generators(UK)];
 
sage: UK.fundamental_units()
 
gp: K.fu
 
Regulator:  \( 7466736411.06 \) (assuming GRH)
magma: Regulator(K);
 
sage: K.regulator()
 
gp: K.reg
 

Galois group

$D_{21}:C_3$ (as 21T10):

magma: GaloisGroup(K);
 
sage: K.galois_group(type='pari')
 
gp: polgalois(K.pol)
 
A solvable group of order 126
The 12 conjugacy class representatives for $D_{21}:C_3$
Character table for $D_{21}:C_3$

Intermediate fields

3.1.108.1, 7.1.155649627.1

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

Sibling fields

Degree 42 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 ${\href{/LocalNumberField/5.6.0.1}{6} }^{3}{,}\,{\href{/LocalNumberField/5.2.0.1}{2} }{,}\,{\href{/LocalNumberField/5.1.0.1}{1} }$ R ${\href{/LocalNumberField/11.6.0.1}{6} }^{3}{,}\,{\href{/LocalNumberField/11.2.0.1}{2} }{,}\,{\href{/LocalNumberField/11.1.0.1}{1} }$ $21$ ${\href{/LocalNumberField/17.6.0.1}{6} }^{3}{,}\,{\href{/LocalNumberField/17.2.0.1}{2} }{,}\,{\href{/LocalNumberField/17.1.0.1}{1} }$ ${\href{/LocalNumberField/19.3.0.1}{3} }^{7}$ ${\href{/LocalNumberField/23.6.0.1}{6} }^{3}{,}\,{\href{/LocalNumberField/23.2.0.1}{2} }{,}\,{\href{/LocalNumberField/23.1.0.1}{1} }$ ${\href{/LocalNumberField/29.2.0.1}{2} }^{10}{,}\,{\href{/LocalNumberField/29.1.0.1}{1} }$ ${\href{/LocalNumberField/31.3.0.1}{3} }^{6}{,}\,{\href{/LocalNumberField/31.1.0.1}{1} }^{3}$ ${\href{/LocalNumberField/37.3.0.1}{3} }^{7}$ ${\href{/LocalNumberField/41.2.0.1}{2} }^{10}{,}\,{\href{/LocalNumberField/41.1.0.1}{1} }$ ${\href{/LocalNumberField/43.7.0.1}{7} }^{3}$ ${\href{/LocalNumberField/47.6.0.1}{6} }^{3}{,}\,{\href{/LocalNumberField/47.2.0.1}{2} }{,}\,{\href{/LocalNumberField/47.1.0.1}{1} }$ ${\href{/LocalNumberField/53.6.0.1}{6} }^{3}{,}\,{\href{/LocalNumberField/53.2.0.1}{2} }{,}\,{\href{/LocalNumberField/53.1.0.1}{1} }$ ${\href{/LocalNumberField/59.6.0.1}{6} }^{3}{,}\,{\href{/LocalNumberField/59.2.0.1}{2} }{,}\,{\href{/LocalNumberField/59.1.0.1}{1} }$

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
2Data not computed
3Data not computed
7Data not computed