Properties

Label 21.21.467...001.1
Degree $21$
Signature $[21, 0]$
Discriminant $4.671\times 10^{32}$
Root discriminant \(35.95\)
Ramified prime $43$
Class number $1$ (GRH)
Class group trivial (GRH)
Galois group $C_{21}$ (as 21T1)

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Normalized defining polynomial

Copy content comment:Define the number field
 
Copy content sage:x = polygen(QQ); K.<a> = NumberField(x^21 - x^20 - 20*x^19 + 19*x^18 + 171*x^17 - 153*x^16 - 816*x^15 + 680*x^14 + 2380*x^13 - 1820*x^12 - 4368*x^11 + 3003*x^10 + 5005*x^9 - 3003*x^8 - 3432*x^7 + 1716*x^6 + 1287*x^5 - 495*x^4 - 220*x^3 + 55*x^2 + 11*x - 1)
 
Copy content gp:K = bnfinit(y^21 - y^20 - 20*y^19 + 19*y^18 + 171*y^17 - 153*y^16 - 816*y^15 + 680*y^14 + 2380*y^13 - 1820*y^12 - 4368*y^11 + 3003*y^10 + 5005*y^9 - 3003*y^8 - 3432*y^7 + 1716*y^6 + 1287*y^5 - 495*y^4 - 220*y^3 + 55*y^2 + 11*y - 1, 1)
 
Copy content magma:R<x> := PolynomialRing(Rationals()); K<a> := NumberField(x^21 - x^20 - 20*x^19 + 19*x^18 + 171*x^17 - 153*x^16 - 816*x^15 + 680*x^14 + 2380*x^13 - 1820*x^12 - 4368*x^11 + 3003*x^10 + 5005*x^9 - 3003*x^8 - 3432*x^7 + 1716*x^6 + 1287*x^5 - 495*x^4 - 220*x^3 + 55*x^2 + 11*x - 1);
 
Copy content oscar:Qx, x = polynomial_ring(QQ); K, a = number_field(x^21 - x^20 - 20*x^19 + 19*x^18 + 171*x^17 - 153*x^16 - 816*x^15 + 680*x^14 + 2380*x^13 - 1820*x^12 - 4368*x^11 + 3003*x^10 + 5005*x^9 - 3003*x^8 - 3432*x^7 + 1716*x^6 + 1287*x^5 - 495*x^4 - 220*x^3 + 55*x^2 + 11*x - 1)
 

\( x^{21} - x^{20} - 20 x^{19} + 19 x^{18} + 171 x^{17} - 153 x^{16} - 816 x^{15} + 680 x^{14} + 2380 x^{13} + \cdots - 1 \) Copy content Toggle raw display

Copy content comment:Defining polynomial
 
Copy content sage:K.defining_polynomial()
 
Copy content gp:K.pol
 
Copy content magma:DefiningPolynomial(K);
 
Copy content oscar:defining_polynomial(K)
 

Invariants

Degree:  $21$
Copy content comment:Degree over Q
 
Copy content sage:K.degree()
 
Copy content gp:poldegree(K.pol)
 
Copy content magma:Degree(K);
 
Copy content oscar:degree(K)
 
Signature:  $[21, 0]$
Copy content comment:Signature
 
Copy content sage:K.signature()
 
Copy content gp:K.sign
 
Copy content magma:Signature(K);
 
Copy content oscar:signature(K)
 
Discriminant:   \(467056167777397914441056671494001\) \(\medspace = 43^{20}\) Copy content Toggle raw display
Copy content comment:Discriminant
 
Copy content sage:K.disc()
 
Copy content gp:K.disc
 
Copy content magma:OK := Integers(K); Discriminant(OK);
 
Copy content oscar:OK = ring_of_integers(K); discriminant(OK)
 
Root discriminant:  \(35.95\)
Copy content sage:(K.disc().abs())^(1./K.degree())
 
Copy content gp:abs(K.disc)^(1/poldegree(K.pol))
 
Copy content magma:Abs(Discriminant(OK))^(1/Degree(K));
 
Copy content oscar:(1.0 * dK)^(1/degree(K))
 
Galois root discriminant:  $43^{20/21}\approx 35.948787215302666$
Ramified primes:   \(43\) Copy content Toggle raw display
Copy content comment:Ramified primes
 
Copy content sage:K.disc().support()
 
Copy content gp:factor(abs(K.disc))[,1]~
 
Copy content magma:PrimeDivisors(Discriminant(OK));
 
Copy content oscar:prime_divisors(discriminant((OK)))
 
Discriminant root field:  \(\Q\)
$\Aut(K/\Q)$ $=$ $\Gal(K/\Q)$:   $C_{21}$
Copy content comment:Autmorphisms
 
Copy content sage:K.automorphisms()
 
Copy content magma:Automorphisms(K);
 
Copy content oscar:automorphisms(K)
 
This field is Galois and abelian over $\Q$.
Conductor:  \(43\)
Dirichlet character group:    $\lbrace$$\chi_{43}(1,·)$, $\chi_{43}(4,·)$, $\chi_{43}(6,·)$, $\chi_{43}(9,·)$, $\chi_{43}(10,·)$, $\chi_{43}(11,·)$, $\chi_{43}(13,·)$, $\chi_{43}(14,·)$, $\chi_{43}(15,·)$, $\chi_{43}(16,·)$, $\chi_{43}(17,·)$, $\chi_{43}(21,·)$, $\chi_{43}(23,·)$, $\chi_{43}(24,·)$, $\chi_{43}(25,·)$, $\chi_{43}(31,·)$, $\chi_{43}(35,·)$, $\chi_{43}(36,·)$, $\chi_{43}(38,·)$, $\chi_{43}(40,·)$, $\chi_{43}(41,·)$$\rbrace$
This is not a CM field.
This field has no CM subfields.

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

$1$, $a$, $a^{2}$, $a^{3}$, $a^{4}$, $a^{5}$, $a^{6}$, $a^{7}$, $a^{8}$, $a^{9}$, $a^{10}$, $a^{11}$, $a^{12}$, $a^{13}$, $a^{14}$, $a^{15}$, $a^{16}$, $a^{17}$, $a^{18}$, $a^{19}$, $a^{20}$ Copy content Toggle raw display

Copy content comment:Integral basis
 
Copy content sage:K.integral_basis()
 
Copy content gp:K.zk
 
Copy content magma:IntegralBasis(K);
 
Copy content oscar:basis(OK)
 

Monogenic:  Yes
Index:  $1$
Inessential primes:  None

Class group and class number

Ideal class group:  Trivial group, which has order $1$ (assuming GRH)
Copy content comment:Class group
 
Copy content sage:K.class_group().invariants()
 
Copy content gp:K.clgp
 
Copy content magma:ClassGroup(K);
 
Copy content oscar:class_group(K)
 
Narrow class group:  Trivial group, which has order $1$ (assuming GRH)
Copy content comment:Narrow class group
 
Copy content sage:K.narrow_class_group().invariants()
 
Copy content gp:bnfnarrow(K)
 
Copy content magma:NarrowClassGroup(K);
 

Unit group

Copy content comment:Unit group
 
Copy content sage:UK = K.unit_group()
 
Copy content magma:UK, fUK := UnitGroup(K);
 
Copy content oscar:UK, fUK = unit_group(OK)
 
Rank:  $20$
Copy content comment:Unit rank
 
Copy content sage:UK.rank()
 
Copy content gp:K.fu
 
Copy content magma:UnitRank(K);
 
Copy content oscar:rank(UK)
 
Torsion generator:   \( -1 \)  (order $2$) Copy content Toggle raw display
Copy content comment:Generator for roots of unity
 
Copy content sage:UK.torsion_generator()
 
Copy content gp:K.tu[2]
 
Copy content magma:K!f(TU.1) where TU,f is TorsionUnitGroup(K);
 
Copy content oscar:torsion_units_generator(OK)
 
Fundamental units:   $a^{10}-a^{9}-9a^{8}+8a^{7}+28a^{6}-21a^{5}-35a^{4}+20a^{3}+15a^{2}-5a-1$, $a^{17}-a^{16}-16a^{15}+15a^{14}+105a^{13}-91a^{12}-364a^{11}+287a^{10}+714a^{9}-504a^{8}-784a^{7}+490a^{6}+441a^{5}-245a^{4}-99a^{3}+50a^{2}+2a-1$, $a^{10}-10a^{8}+35a^{6}-50a^{4}+25a^{2}-2$, $a^{19}-a^{18}-18a^{17}+18a^{16}+135a^{15}-135a^{14}-545a^{13}+545a^{12}+1275a^{11}-1275a^{10}-1728a^{9}+1728a^{8}+1275a^{7}-1275a^{6}-441a^{5}+441a^{4}+54a^{3}-54a^{2}-a+1$, $a-1$, $a^{7}-7a^{5}+14a^{3}-7a-1$, $a^{20}-a^{19}-19a^{18}+18a^{17}+153a^{16}-136a^{15}-681a^{14}+561a^{13}+1833a^{12}-1378a^{11}-3068a^{10}+2067a^{9}+3159a^{8}-1872a^{7}-1898a^{6}+975a^{5}+585a^{4}-260a^{3}-64a^{2}+25a-1$, $a^{20}-20a^{18}-a^{17}+170a^{16}+16a^{15}-799a^{14}-104a^{13}+2262a^{12}+351a^{11}-3939a^{10}-650a^{9}+4135a^{8}+637a^{7}-2465a^{6}-287a^{5}+748a^{4}+43a^{3}-94a^{2}-2a+3$, $a^{7}-7a^{5}+14a^{3}-7a$, $a^{20}-19a^{18}+153a^{16}-680a^{14}+1820a^{12}-3003a^{10}+3003a^{8}-1716a^{6}+495a^{4}-55a^{2}+1$, $a^{3}-3a-1$, $a^{9}-9a^{7}+27a^{5}-30a^{3}+9a$, $a^{5}-5a^{3}+5a$, $a^{16}-a^{15}-15a^{14}+14a^{13}+91a^{12}-78a^{11}-286a^{10}+220a^{9}+495a^{8}-330a^{7}-462a^{6}+253a^{5}+209a^{4}-88a^{3}-33a^{2}+11a$, $a^{19}-19a^{17}+152a^{15}-a^{14}-665a^{13}+14a^{12}+1729a^{11}-77a^{10}-2717a^{9}+210a^{8}+2508a^{7}-294a^{6}-1254a^{5}+196a^{4}+285a^{3}-49a^{2}-19a+2$, $a^{12}-12a^{10}-a^{9}+54a^{8}+9a^{7}-111a^{6}-27a^{5}+99a^{4}+29a^{3}-27a^{2}-6a+1$, $a^{3}-3a$, $a^{8}-8a^{6}+21a^{4}-20a^{2}+5$, $a^{16}-16a^{14}+104a^{12}-352a^{10}+661a^{8}-680a^{6}+356a^{4}-80a^{2}+5$, $a^{20}-a^{19}-19a^{18}+19a^{17}+152a^{16}-153a^{15}-664a^{14}+679a^{13}+1715a^{12}-1807a^{11}-2639a^{10}+2937a^{9}+2288a^{8}-2837a^{7}-924a^{6}+1499a^{5}+34a^{4}-354a^{3}+60a^{2}+17a-3$ Copy content Toggle raw display (assuming GRH)
Copy content comment:Fundamental units
 
Copy content sage:UK.fundamental_units()
 
Copy content gp:K.fu
 
Copy content magma:[K|fUK(g): g in Generators(UK)];
 
Copy content oscar:[K(fUK(a)) for a in gens(UK)]
 
Regulator:  \( 2620717953.48 \) (assuming GRH)
Copy content comment:Regulator
 
Copy content sage:K.regulator()
 
Copy content gp:K.reg
 
Copy content magma:Regulator(K);
 
Copy content oscar:regulator(K)
 

Class number formula

\[ \begin{aligned}\lim_{s\to 1} (s-1)\zeta_K(s) =\mathstrut & \frac{2^{r_1}\cdot (2\pi)^{r_2}\cdot R\cdot h}{w\cdot\sqrt{|D|}}\cr \approx\mathstrut &\frac{2^{21}\cdot(2\pi)^{0}\cdot 2620717953.48 \cdot 1}{2\cdot\sqrt{467056167777397914441056671494001}}\cr\approx \mathstrut & 0.127155643882 \end{aligned}\] (assuming GRH)

Copy content comment:Analytic class number formula
 
Copy content sage:# self-contained SageMath code snippet to compute the analytic class number formula x = polygen(QQ); K.<a> = NumberField(x^21 - x^20 - 20*x^19 + 19*x^18 + 171*x^17 - 153*x^16 - 816*x^15 + 680*x^14 + 2380*x^13 - 1820*x^12 - 4368*x^11 + 3003*x^10 + 5005*x^9 - 3003*x^8 - 3432*x^7 + 1716*x^6 + 1287*x^5 - 495*x^4 - 220*x^3 + 55*x^2 + 11*x - 1) DK = K.disc(); r1,r2 = K.signature(); RK = K.regulator(); RR = RK.parent() hK = K.class_number(); wK = K.unit_group().torsion_generator().order(); 2^r1 * (2*RR(pi))^r2 * RK * hK / (wK * RR(sqrt(abs(DK))))
 
Copy content gp:\\ self-contained Pari/GP code snippet to compute the analytic class number formula K = bnfinit(x^21 - x^20 - 20*x^19 + 19*x^18 + 171*x^17 - 153*x^16 - 816*x^15 + 680*x^14 + 2380*x^13 - 1820*x^12 - 4368*x^11 + 3003*x^10 + 5005*x^9 - 3003*x^8 - 3432*x^7 + 1716*x^6 + 1287*x^5 - 495*x^4 - 220*x^3 + 55*x^2 + 11*x - 1, 1); [polcoeff (lfunrootres (lfuncreate (K))[1][1][2], -1), 2^K.r1 * (2*Pi)^K.r2 * K.reg * K.no / (K.tu[1] * sqrt (abs (K.disc)))]
 
Copy content magma:/* self-contained Magma code snippet to compute the analytic class number formula */ Qx<x> := PolynomialRing(Rationals()); K<a> := NumberField(x^21 - x^20 - 20*x^19 + 19*x^18 + 171*x^17 - 153*x^16 - 816*x^15 + 680*x^14 + 2380*x^13 - 1820*x^12 - 4368*x^11 + 3003*x^10 + 5005*x^9 - 3003*x^8 - 3432*x^7 + 1716*x^6 + 1287*x^5 - 495*x^4 - 220*x^3 + 55*x^2 + 11*x - 1); OK := Integers(K); DK := Discriminant(OK); UK, fUK := UnitGroup(OK); clK, fclK := ClassGroup(OK); r1,r2 := Signature(K); RK := Regulator(K); RR := Parent(RK); hK := #clK; wK := #TorsionSubgroup(UK); 2^r1 * (2*Pi(RR))^r2 * RK * hK / (wK * Sqrt(RR!Abs(DK)));
 
Copy content oscar:# self-contained Oscar code snippet to compute the analytic class number formula Qx, x = PolynomialRing(QQ); K, a = NumberField(x^21 - x^20 - 20*x^19 + 19*x^18 + 171*x^17 - 153*x^16 - 816*x^15 + 680*x^14 + 2380*x^13 - 1820*x^12 - 4368*x^11 + 3003*x^10 + 5005*x^9 - 3003*x^8 - 3432*x^7 + 1716*x^6 + 1287*x^5 - 495*x^4 - 220*x^3 + 55*x^2 + 11*x - 1); OK = ring_of_integers(K); DK = discriminant(OK); UK, fUK = unit_group(OK); clK, fclK = class_group(OK); r1,r2 = signature(K); RK = regulator(K); RR = parent(RK); hK = order(clK); wK = torsion_units_order(K); 2^r1 * (2*pi)^r2 * RK * hK / (wK * sqrt(RR(abs(DK))))
 

Galois group

$C_{21}$ (as 21T1):

Copy content comment:Galois group
 
Copy content sage:K.galois_group(type='pari')
 
Copy content gp:polgalois(K.pol)
 
Copy content magma:G = GaloisGroup(K);
 
Copy content oscar:G, Gtx = galois_group(K); G, transitive_group_identification(G)
 
A cyclic group of order 21
The 21 conjugacy class representatives for $C_{21}$
Character table for $C_{21}$

Intermediate fields

3.3.1849.1, 7.7.6321363049.1

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

Copy content comment:Intermediate fields
 
Copy content sage:K.subfields()[1:-1]
 
Copy content gp:L = nfsubfields(K); L[2..length(b)]
 
Copy content magma:L := Subfields(K); L[2..#L];
 
Copy content oscar:subfields(K)[2:end-1]
 

Frobenius cycle types

$p$ $2$ $3$ $5$ $7$ $11$ $13$ $17$ $19$ $23$ $29$ $31$ $37$ $41$ $43$ $47$ $53$ $59$
Cycle type ${\href{/padicField/2.7.0.1}{7} }^{3}$ $21$ $21$ ${\href{/padicField/7.3.0.1}{3} }^{7}$ ${\href{/padicField/11.7.0.1}{7} }^{3}$ $21$ $21$ $21$ $21$ $21$ $21$ ${\href{/padicField/37.3.0.1}{3} }^{7}$ ${\href{/padicField/41.7.0.1}{7} }^{3}$ R ${\href{/padicField/47.7.0.1}{7} }^{3}$ $21$ ${\href{/padicField/59.7.0.1}{7} }^{3}$

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

Copy content comment:Frobenius cycle types
 
Copy content sage:# to obtain a list of [e_i,f_i] for the factorization of the ideal pO_K for p=7 in Sage: p = 7; [(e, pr.norm().valuation(p)) for pr,e in K.factor(p)]
 
Copy content gp:\\ to obtain a list of [e_i,f_i] for the factorization of the ideal pO_K for p=7 in Pari: p = 7; pfac = idealprimedec(K, p); vector(length(pfac), j, [pfac[j][3], pfac[j][4]])
 
Copy content magma:// to obtain a list of [e_i,f_i] for the factorization of the ideal pO_K for p=7 in Magma: p := 7; [<pr[2], Valuation(Norm(pr[1]), p)> : pr in Factorization(p*Integers(K))];
 
Copy content oscar:# to obtain a list of [e_i,f_i] for the factorization of the ideal pO_K for p=7 in Oscar: p = 7; pfac = factor(ideal(ring_of_integers(K), p)); [(e, valuation(norm(pr),p)) for (pr,e) in pfac]
 

Local algebras for ramified primes

$p$LabelPolynomial $e$ $f$ $c$ Galois group Slope content
\(43\) Copy content Toggle raw display 43.1.21.20a1.1$x^{21} + 43$$21$$1$$20$$C_{21}$$$[\ ]_{21}$$

Spectrum of ring of integers

(0)(0)(2)(3)(5)(7)(11)(13)(17)(19)(23)(29)(31)(37)(41)(43)(47)(53)(59)