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Properties

Label 16.8.737...464.2
Degree $16$
Signature $[8, 4]$
Discriminant $7.379\times 10^{19}$
Root discriminant \(17.45\)
Ramified prime $2$
Class number $1$ (GRH)
Class group trivial (GRH)
Galois group $C_2^2 : C_8$ (as 16T24)

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Show commands: Magma / Oscar / Pari/GP / SageMath

Normalized defining polynomial

Copy content comment:Define the number field
 
Copy content sage:x = polygen(QQ); K.<a> = NumberField(x^16 - 8*x^14 + 12*x^12 - 8*x^10 + 42*x^8 - 72*x^6 + 36*x^4 - 8*x^2 + 1)
 
Copy content gp:K = bnfinit(y^16 - 8*y^14 + 12*y^12 - 8*y^10 + 42*y^8 - 72*y^6 + 36*y^4 - 8*y^2 + 1, 1)
 
Copy content magma:R<x> := PolynomialRing(Rationals()); K<a> := NumberField(x^16 - 8*x^14 + 12*x^12 - 8*x^10 + 42*x^8 - 72*x^6 + 36*x^4 - 8*x^2 + 1);
 
Copy content oscar:Qx, x = polynomial_ring(QQ); K, a = number_field(x^16 - 8*x^14 + 12*x^12 - 8*x^10 + 42*x^8 - 72*x^6 + 36*x^4 - 8*x^2 + 1)
 

\( x^{16} - 8x^{14} + 12x^{12} - 8x^{10} + 42x^{8} - 72x^{6} + 36x^{4} - 8x^{2} + 1 \) 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:  $16$
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:  $[8, 4]$
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:   \(73786976294838206464\) \(\medspace = 2^{66}\) 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:  \(17.45\)
Copy content comment:Root discriminant
 
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:OK = ring_of_integers(K); (1.0 * abs(discriminant(OK)))^(1/degree(K))
 
Galois root discriminant:  $2^{67/16}\approx 18.220618156107065$
Ramified primes:   \(2\) 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:  \(\Q\)
$\Aut(K/\Q)$:   $C_2\times C_4$
Copy content comment:Autmorphisms
 
Copy content sage:K.automorphisms()
 
Copy content magma:Automorphisms(K);
 
Copy content oscar:automorphisms(K)
 
This field is not Galois over $\Q$.
This is not a CM field.
This field has no CM subfields.

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

$1$, $a$, $a^{2}$, $a^{3}$, $a^{4}$, $a^{5}$, $a^{6}$, $a^{7}$, $\frac{1}{2}a^{8}-\frac{1}{2}$, $\frac{1}{4}a^{9}-\frac{1}{4}a^{8}-\frac{1}{2}a^{7}-\frac{1}{2}a^{6}-\frac{1}{2}a^{5}-\frac{1}{2}a^{4}-\frac{1}{2}a^{3}-\frac{1}{2}a^{2}-\frac{1}{4}a+\frac{1}{4}$, $\frac{1}{4}a^{10}-\frac{1}{4}a^{8}+\frac{1}{4}a^{2}-\frac{1}{4}$, $\frac{1}{4}a^{11}-\frac{1}{4}a^{8}-\frac{1}{2}a^{7}-\frac{1}{2}a^{6}-\frac{1}{2}a^{5}-\frac{1}{2}a^{4}-\frac{1}{4}a^{3}-\frac{1}{2}a^{2}-\frac{1}{2}a+\frac{1}{4}$, $\frac{1}{4}a^{12}-\frac{1}{4}a^{8}+\frac{1}{4}a^{4}-\frac{1}{4}$, $\frac{1}{4}a^{13}-\frac{1}{4}a^{8}-\frac{1}{2}a^{7}-\frac{1}{2}a^{6}-\frac{1}{4}a^{5}-\frac{1}{2}a^{4}-\frac{1}{2}a^{3}-\frac{1}{2}a^{2}-\frac{1}{2}a+\frac{1}{4}$, $\frac{1}{1028}a^{14}-\frac{25}{1028}a^{12}-\frac{77}{1028}a^{10}-\frac{241}{1028}a^{8}-\frac{487}{1028}a^{6}-\frac{17}{1028}a^{4}-\frac{189}{1028}a^{2}-\frac{393}{1028}$, $\frac{1}{1028}a^{15}-\frac{25}{1028}a^{13}-\frac{77}{1028}a^{11}+\frac{4}{257}a^{9}-\frac{1}{4}a^{8}+\frac{27}{1028}a^{7}-\frac{1}{2}a^{6}+\frac{497}{1028}a^{5}-\frac{1}{2}a^{4}+\frac{325}{1028}a^{3}-\frac{1}{2}a^{2}+\frac{189}{514}a+\frac{1}{4}$ 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:  Not computed
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:  $11$
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:   $\frac{111}{514}a^{14}-\frac{1695}{1028}a^{12}+\frac{481}{257}a^{10}-\frac{303}{1028}a^{8}+\frac{4539}{514}a^{6}-\frac{12255}{1028}a^{4}-\frac{81}{257}a^{2}-\frac{123}{1028}$, $\frac{99}{1028}a^{15}-\frac{933}{1028}a^{13}+\frac{2143}{1028}a^{11}-\frac{1243}{1028}a^{9}+\frac{4215}{1028}a^{7}-\frac{12477}{1028}a^{5}+\frac{7503}{1028}a^{3}+\frac{157}{1028}a$, $a$, $\frac{122}{257}a^{15}-\frac{994}{257}a^{13}+\frac{6371}{1028}a^{11}-\frac{4271}{1028}a^{9}+\frac{5093}{257}a^{7}-\frac{9527}{257}a^{5}+\frac{19563}{1028}a^{3}-\frac{2375}{1028}a$, $\frac{99}{1028}a^{15}+\frac{51}{1028}a^{14}-\frac{933}{1028}a^{13}-\frac{247}{1028}a^{12}+\frac{2143}{1028}a^{11}-\frac{293}{514}a^{10}-\frac{1243}{1028}a^{9}+\frac{204}{257}a^{8}+\frac{4215}{1028}a^{7}+\frac{1891}{1028}a^{6}-\frac{12477}{1028}a^{5}+\frac{2217}{1028}a^{4}+\frac{7503}{1028}a^{3}-\frac{3149}{514}a^{2}+\frac{157}{1028}a+\frac{65}{257}$, $a^{15}+\frac{383}{1028}a^{14}-8a^{13}-\frac{2893}{1028}a^{12}+12a^{11}+\frac{787}{257}a^{10}-8a^{9}-\frac{277}{514}a^{8}+42a^{7}+\frac{14967}{1028}a^{6}-72a^{5}-\frac{20389}{1028}a^{4}+36a^{3}-\frac{171}{257}a^{2}-8a+\frac{941}{514}$, $\frac{333}{1028}a^{15}+\frac{573}{1028}a^{14}-\frac{1207}{514}a^{13}-\frac{2151}{514}a^{12}+\frac{2115}{1028}a^{11}+\frac{4709}{1028}a^{10}-\frac{583}{1028}a^{9}-\frac{1883}{1028}a^{8}+\frac{13103}{1028}a^{7}+\frac{22667}{1028}a^{6}-\frac{3407}{257}a^{5}-\frac{7511}{257}a^{4}-\frac{1771}{1028}a^{3}+\frac{4783}{1028}a^{2}-\frac{1341}{1028}a-\frac{1085}{1028}$, $\frac{32}{257}a^{15}-\frac{105}{514}a^{14}-\frac{286}{257}a^{13}+\frac{413}{257}a^{12}+\frac{620}{257}a^{11}-\frac{1167}{514}a^{10}-\frac{2321}{1028}a^{9}+\frac{1523}{1028}a^{8}+\frac{3013}{514}a^{7}-\frac{2060}{257}a^{6}-\frac{6999}{514}a^{5}+\frac{6925}{514}a^{4}+\frac{6151}{514}a^{3}-\frac{1514}{257}a^{2}-\frac{1731}{1028}a+\frac{1061}{1028}$, $\frac{461}{1028}a^{15}+\frac{783}{1028}a^{14}-\frac{1779}{514}a^{13}-\frac{2977}{514}a^{12}+\frac{4595}{1028}a^{11}+\frac{7043}{1028}a^{10}-\frac{726}{257}a^{9}-\frac{1703}{514}a^{8}+\frac{19129}{1028}a^{7}+\frac{30907}{1028}a^{6}-\frac{13813}{514}a^{5}-\frac{21947}{514}a^{4}+\frac{10531}{1028}a^{3}+\frac{10839}{1028}a^{2}-\frac{768}{257}a-\frac{559}{514}$, $\frac{1621}{1028}a^{15}-\frac{95}{514}a^{14}-\frac{12769}{1028}a^{13}+\frac{1409}{1028}a^{12}+\frac{8909}{514}a^{11}-\frac{1561}{1028}a^{10}-\frac{10301}{1028}a^{9}+\frac{1329}{1028}a^{8}+\frac{66383}{1028}a^{7}-\frac{1925}{257}a^{6}-\frac{108255}{1028}a^{5}+\frac{9655}{1028}a^{4}+\frac{10595}{257}a^{3}-\frac{5467}{1028}a^{2}-\frac{5347}{1028}a+\frac{1939}{1028}$, $\frac{1621}{1028}a^{15}+\frac{95}{514}a^{14}-\frac{12769}{1028}a^{13}-\frac{1409}{1028}a^{12}+\frac{8909}{514}a^{11}+\frac{1561}{1028}a^{10}-\frac{10301}{1028}a^{9}-\frac{1329}{1028}a^{8}+\frac{66383}{1028}a^{7}+\frac{1925}{257}a^{6}-\frac{108255}{1028}a^{5}-\frac{9655}{1028}a^{4}+\frac{10595}{257}a^{3}+\frac{5467}{1028}a^{2}-\frac{5347}{1028}a-\frac{1939}{1028}$ 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:  \( 13514.1847612 \) (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

\[ \begin{aligned}\lim_{s\to 1} (s-1)\zeta_K(s) =\mathstrut & \frac{2^{r_1}\cdot (2\pi)^{r_2}\cdot R\cdot h}{w\cdot\sqrt{|D|}}\cr \approx\mathstrut &\frac{2^{8}\cdot(2\pi)^{4}\cdot 13514.1847612 \cdot 1}{2\cdot\sqrt{73786976294838206464}}\cr\approx \mathstrut & 0.313855279363 \end{aligned}\] (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^16 - 8*x^14 + 12*x^12 - 8*x^10 + 42*x^8 - 72*x^6 + 36*x^4 - 8*x^2 + 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^16 - 8*x^14 + 12*x^12 - 8*x^10 + 42*x^8 - 72*x^6 + 36*x^4 - 8*x^2 + 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^16 - 8*x^14 + 12*x^12 - 8*x^10 + 42*x^8 - 72*x^6 + 36*x^4 - 8*x^2 + 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 = polynomial_ring(QQ); K, a = number_field(x^16 - 8*x^14 + 12*x^12 - 8*x^10 + 42*x^8 - 72*x^6 + 36*x^4 - 8*x^2 + 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

$C_2^2:C_8$ (as 16T24):

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); degree(K) > 1 ? (G, transitive_group_identification(G)) : (G, nothing)
 
A solvable group of order 32
The 20 conjugacy class representatives for $C_2^2 : C_8$
Character table for $C_2^2 : C_8$

Intermediate fields

\(\Q(\sqrt{2}) \), \(\Q(\zeta_{16})^+\), 4.2.1024.1, 4.2.2048.1, 8.4.2147483648.1, \(\Q(\zeta_{32})^+\), 8.4.67108864.1

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(L)]
 
Copy content magma:L := Subfields(K); L[2..#L];
 
Copy content oscar:subfields(K)[2:end-1]
 

Sibling fields

Galois closure: deg 32
Degree 16 sibling: 16.0.73786976294838206464.5
Minimal sibling: This field is its own minimal sibling

Frobenius cycle types

$p$ $2$ $3$ $5$ $7$ $11$ $13$ $17$ $19$ $23$ $29$ $31$ $37$ $41$ $43$ $47$ $53$ $59$
Cycle type R ${\href{/padicField/3.8.0.1}{8} }^{2}$ ${\href{/padicField/5.8.0.1}{8} }^{2}$ ${\href{/padicField/7.4.0.1}{4} }^{4}$ ${\href{/padicField/11.8.0.1}{8} }^{2}$ ${\href{/padicField/13.8.0.1}{8} }^{2}$ ${\href{/padicField/17.2.0.1}{2} }^{8}$ ${\href{/padicField/19.8.0.1}{8} }^{2}$ ${\href{/padicField/23.4.0.1}{4} }^{4}$ ${\href{/padicField/29.8.0.1}{8} }^{2}$ ${\href{/padicField/31.2.0.1}{2} }^{4}{,}\,{\href{/padicField/31.1.0.1}{1} }^{8}$ ${\href{/padicField/37.8.0.1}{8} }^{2}$ ${\href{/padicField/41.4.0.1}{4} }^{4}$ ${\href{/padicField/43.8.0.1}{8} }^{2}$ ${\href{/padicField/47.2.0.1}{2} }^{8}$ ${\href{/padicField/53.8.0.1}{8} }^{2}$ ${\href{/padicField/59.8.0.1}{8} }^{2}$

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
\(2\) Copy content Toggle raw display 2.1.16.66h1.265$x^{16} + 8 x^{14} + 4 x^{12} + 8 x^{10} + 8 x^{6} + 16 x^{5} + 16 x^{3} + 2$$16$$1$$66$$C_2^2 : C_8$$$[2, 3, \frac{7}{2}, 4, 5]$$

Spectrum of ring of integers

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