Properties

Label 16.0.106...816.2
Degree $16$
Signature $[0, 8]$
Discriminant $1.065\times 10^{25}$
Root discriminant \(36.66\)
Ramified primes $2,3,7$
Class number $128$ (GRH)
Class group [4, 4, 8] (GRH)
Galois group $C_4\times C_2^2$ (as 16T2)

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Show commands: Magma / Oscar / PariGP / SageMath

Normalized defining polynomial

sage: x = polygen(QQ); K.<a> = NumberField(x^16 + 24*x^14 + 276*x^12 + 1776*x^10 + 6881*x^8 + 15072*x^6 + 16704*x^4 + 3072*x^2 + 256)
 
gp: K = bnfinit(y^16 + 24*y^14 + 276*y^12 + 1776*y^10 + 6881*y^8 + 15072*y^6 + 16704*y^4 + 3072*y^2 + 256, 1)
 
magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(x^16 + 24*x^14 + 276*x^12 + 1776*x^10 + 6881*x^8 + 15072*x^6 + 16704*x^4 + 3072*x^2 + 256);
 
oscar: Qx, x = PolynomialRing(QQ); K, a = NumberField(x^16 + 24*x^14 + 276*x^12 + 1776*x^10 + 6881*x^8 + 15072*x^6 + 16704*x^4 + 3072*x^2 + 256)
 

\( x^{16} + 24x^{14} + 276x^{12} + 1776x^{10} + 6881x^{8} + 15072x^{6} + 16704x^{4} + 3072x^{2} + 256 \) Copy content Toggle raw display

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

Invariants

Degree:  $16$
sage: K.degree()
 
gp: poldegree(K.pol)
 
magma: Degree(K);
 
oscar: degree(K)
 
Signature:  $[0, 8]$
sage: K.signature()
 
gp: K.sign
 
magma: Signature(K);
 
oscar: signature(K)
 
Discriminant:   \(10646188457767892278050816\) \(\medspace = 2^{48}\cdot 3^{8}\cdot 7^{8}\) Copy content Toggle raw display
sage: K.disc()
 
gp: K.disc
 
magma: OK := Integers(K); Discriminant(OK);
 
oscar: OK = ring_of_integers(K); discriminant(OK)
 
Root discriminant:  \(36.66\)
sage: (K.disc().abs())^(1./K.degree())
 
gp: abs(K.disc)^(1/poldegree(K.pol))
 
magma: Abs(Discriminant(OK))^(1/Degree(K));
 
oscar: (1.0 * dK)^(1/degree(K))
 
Galois root discriminant:  $2^{3}3^{1/2}7^{1/2}\approx 36.66060555964672$
Ramified primes:   \(2\), \(3\), \(7\) Copy content Toggle raw display
sage: K.disc().support()
 
gp: factor(abs(K.disc))[,1]~
 
magma: PrimeDivisors(Discriminant(OK));
 
oscar: prime_divisors(discriminant((OK)))
 
Discriminant root field:  \(\Q\)
$\card{ \Gal(K/\Q) }$:  $16$
sage: K.automorphisms()
 
magma: Automorphisms(K);
 
oscar: automorphisms(K)
 
This field is Galois and abelian over $\Q$.
Conductor:  \(336=2^{4}\cdot 3\cdot 7\)
Dirichlet character group:    $\lbrace$$\chi_{336}(1,·)$, $\chi_{336}(323,·)$, $\chi_{336}(71,·)$, $\chi_{336}(265,·)$, $\chi_{336}(13,·)$, $\chi_{336}(335,·)$, $\chi_{336}(83,·)$, $\chi_{336}(85,·)$, $\chi_{336}(155,·)$, $\chi_{336}(97,·)$, $\chi_{336}(167,·)$, $\chi_{336}(169,·)$, $\chi_{336}(239,·)$, $\chi_{336}(181,·)$, $\chi_{336}(251,·)$, $\chi_{336}(253,·)$$\rbrace$
This is a CM field.
Reflex fields:  unavailable$^{128}$

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

$1$, $a$, $a^{2}$, $a^{3}$, $a^{4}$, $a^{5}$, $a^{6}$, $a^{7}$, $a^{8}$, $\frac{1}{2}a^{9}-\frac{1}{2}a$, $\frac{1}{4}a^{10}+\frac{1}{4}a^{2}$, $\frac{1}{8}a^{11}-\frac{1}{2}a^{7}+\frac{1}{8}a^{3}$, $\frac{1}{16}a^{12}+\frac{1}{4}a^{8}+\frac{1}{16}a^{4}-\frac{1}{2}a^{2}$, $\frac{1}{32}a^{13}+\frac{1}{8}a^{9}-\frac{1}{2}a^{7}+\frac{1}{32}a^{5}+\frac{1}{4}a^{3}-\frac{1}{2}a$, $\frac{1}{131740406848}a^{14}-\frac{288317131}{16467550856}a^{12}+\frac{3477765633}{32935101712}a^{10}-\frac{2630820465}{8233775428}a^{8}-\frac{783465785}{5727843776}a^{6}+\frac{3721719239}{8233775428}a^{4}-\frac{3824511325}{8233775428}a^{2}-\frac{758504595}{2058443857}$, $\frac{1}{263480813696}a^{15}-\frac{288317131}{32935101712}a^{13}+\frac{3477765633}{65870203424}a^{11}-\frac{2630820465}{16467550856}a^{9}+\frac{4944377991}{11455687552}a^{7}+\frac{3721719239}{16467550856}a^{5}-\frac{3824511325}{16467550856}a^{3}-\frac{758504595}{4116887714}a$ Copy content Toggle raw display

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

Monogenic:  Not computed
Index:  $1$
Inessential primes:  None

Class group and class number

$C_{4}\times C_{4}\times C_{8}$, which has order $128$ (assuming GRH)

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

Unit group

sage: UK = K.unit_group()
 
magma: UK, fUK := UnitGroup(K);
 
oscar: UK, fUK = unit_group(OK)
 
Rank:  $7$
sage: UK.rank()
 
gp: K.fu
 
magma: UnitRank(K);
 
oscar: rank(UK)
 
Torsion generator:   \( -1 \)  (order $2$) Copy content Toggle raw display
sage: UK.torsion_generator()
 
gp: K.tu[2]
 
magma: K!f(TU.1) where TU,f is TorsionUnitGroup(K);
 
oscar: torsion_units_generator(OK)
 
Fundamental units:   $\frac{10031865}{131740406848}a^{14}+\frac{9631167}{4116887714}a^{12}+\frac{971132253}{32935101712}a^{10}+\frac{1635605153}{8233775428}a^{8}+\frac{3957468879}{5727843776}a^{6}+\frac{18428854717}{16467550856}a^{4}+\frac{438338082}{2058443857}a^{2}+\frac{1103096384}{2058443857}$, $\frac{457506371}{263480813696}a^{15}+\frac{2784184685}{65870203424}a^{13}+\frac{32359760771}{65870203424}a^{11}+\frac{13163478911}{4116887714}a^{9}+\frac{142814966165}{11455687552}a^{7}+\frac{1792134708547}{65870203424}a^{5}+\frac{467018857015}{16467550856}a^{3}+\frac{4183940842}{2058443857}a$, $\frac{5002089}{4116887714}a^{15}+\frac{59306438}{2058443857}a^{13}+\frac{5394133739}{16467550856}a^{11}+\frac{4269983224}{2058443857}a^{9}+\frac{704830600}{89497559}a^{7}+\frac{34342691200}{2058443857}a^{5}+\frac{286600651155}{16467550856}a^{3}+\frac{2566542133}{2058443857}a$, $\frac{331527}{178995118}a^{15}-\frac{15705}{80673856}a^{14}+\frac{3925864}{89497559}a^{13}-\frac{12439}{2521058}a^{12}+\frac{356717709}{715980472}a^{11}-\frac{1149777}{20168464}a^{10}+\frac{563993821}{178995118}a^{9}-\frac{1794777}{5042116}a^{8}+\frac{1069044024}{89497559}a^{7}-\frac{98278713}{80673856}a^{6}+\frac{2258217632}{89497559}a^{5}-\frac{19612893}{10084232}a^{4}+\frac{18898398181}{715980472}a^{3}-\frac{1864017}{5042116}a^{2}+\frac{338415801}{178995118}a+\frac{482225}{1260529}$, $\frac{331527}{178995118}a^{15}+\frac{3925864}{89497559}a^{13}+\frac{356717709}{715980472}a^{11}+\frac{563993821}{178995118}a^{9}+\frac{1069044024}{89497559}a^{7}+\frac{2258217632}{89497559}a^{5}+\frac{18898398181}{715980472}a^{3}+\frac{338415801}{178995118}a-1$, $\frac{945514115}{263480813696}a^{15}-\frac{15705}{80673856}a^{14}+\frac{5673620589}{65870203424}a^{13}-\frac{12439}{2521058}a^{12}+\frac{65177789999}{65870203424}a^{11}-\frac{1149777}{20168464}a^{10}+\frac{13067668397}{2058443857}a^{9}-\frac{1794777}{5042116}a^{8}+\frac{279652601237}{11455687552}a^{7}-\frac{98278713}{80673856}a^{6}+\frac{3454182885699}{65870203424}a^{5}-\frac{19612893}{10084232}a^{4}+\frac{450841007589}{8233775428}a^{3}-\frac{1864017}{5042116}a^{2}+\frac{16151445107}{4116887714}a+\frac{1742754}{1260529}$, $\frac{10248153}{4116887714}a^{15}-\frac{315}{1099009}a^{14}+\frac{121283306}{2058443857}a^{13}-\frac{114047}{17584144}a^{12}+\frac{11014880875}{16467550856}a^{11}-\frac{154299}{2198018}a^{10}+\frac{8701874659}{2058443857}a^{9}-\frac{1815787}{4396036}a^{8}+\frac{1433257448}{89497559}a^{7}-\frac{66360}{47783}a^{6}+\frac{69535319872}{2058443857}a^{5}-\frac{38437391}{17584144}a^{4}+\frac{582725665171}{16467550856}a^{3}-\frac{456153}{1099009}a^{2}+\frac{5217021290}{2058443857}a+\frac{765505}{1099009}$ Copy content Toggle raw display (assuming GRH)
sage: UK.fundamental_units()
 
gp: K.fu
 
magma: [K|fUK(g): g in Generators(UK)];
 
oscar: [K(fUK(a)) for a in gens(UK)]
 
Regulator:  \( 11964.3106427 \) (assuming GRH)
sage: K.regulator()
 
gp: K.reg
 
magma: Regulator(K);
 
oscar: regulator(K)
 

Class number formula

\[ \begin{aligned}\lim_{s\to 1} (s-1)\zeta_K(s) =\mathstrut & \frac{2^{r_1}\cdot (2\pi)^{r_2}\cdot R\cdot h}{w\cdot\sqrt{|D|}}\cr \approx\mathstrut &\frac{2^{0}\cdot(2\pi)^{8}\cdot 11964.3106427 \cdot 128}{2\cdot\sqrt{10646188457767892278050816}}\cr\approx \mathstrut & 0.570045506429 \end{aligned}\] (assuming GRH)

# self-contained SageMath code snippet to compute the analytic class number formula
 
x = polygen(QQ); K.<a> = NumberField(x^16 + 24*x^14 + 276*x^12 + 1776*x^10 + 6881*x^8 + 15072*x^6 + 16704*x^4 + 3072*x^2 + 256)
 
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))))
 
# self-contained Pari/GP code snippet to compute the analytic class number formula
 
K = bnfinit(x^16 + 24*x^14 + 276*x^12 + 1776*x^10 + 6881*x^8 + 15072*x^6 + 16704*x^4 + 3072*x^2 + 256, 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)))]
 
/* self-contained Magma code snippet to compute the analytic class number formula */
 
Qx<x> := PolynomialRing(QQ); K<a> := NumberField(x^16 + 24*x^14 + 276*x^12 + 1776*x^10 + 6881*x^8 + 15072*x^6 + 16704*x^4 + 3072*x^2 + 256);
 
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)));
 
# self-contained Oscar code snippet to compute the analytic class number formula
 
Qx, x = PolynomialRing(QQ); K, a = NumberField(x^16 + 24*x^14 + 276*x^12 + 1776*x^10 + 6881*x^8 + 15072*x^6 + 16704*x^4 + 3072*x^2 + 256);
 
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

$C_2^2\times C_4$ (as 16T2):

sage: K.galois_group(type='pari')
 
gp: polgalois(K.pol)
 
magma: G = GaloisGroup(K);
 
oscar: G, Gtx = galois_group(K); G, transitive_group_identification(G)
 
An abelian group of order 16
The 16 conjugacy class representatives for $C_4\times C_2^2$
Character table for $C_4\times C_2^2$

Intermediate fields

\(\Q(\sqrt{3}) \), \(\Q(\sqrt{-7}) \), \(\Q(\sqrt{-21}) \), \(\Q(\sqrt{2}) \), \(\Q(\sqrt{6}) \), \(\Q(\sqrt{-14}) \), \(\Q(\sqrt{-42}) \), \(\Q(\sqrt{3}, \sqrt{-7})\), \(\Q(\sqrt{2}, \sqrt{3})\), \(\Q(\sqrt{3}, \sqrt{-14})\), \(\Q(\sqrt{2}, \sqrt{-7})\), \(\Q(\sqrt{6}, \sqrt{-7})\), \(\Q(\sqrt{2}, \sqrt{-21})\), \(\Q(\sqrt{6}, \sqrt{-14})\), 4.4.18432.1, \(\Q(\zeta_{16})^+\), 4.0.903168.5, 4.0.100352.5, 8.0.12745506816.6, \(\Q(\zeta_{48})^+\), 8.0.3262849744896.3, 8.0.815712436224.3, 8.0.10070523904.2, 8.0.3262849744896.2, 8.0.3262849744896.5

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

sage: K.subfields()[1:-1]
 
gp: L = nfsubfields(K); L[2..length(b)]
 
magma: L := Subfields(K); L[2..#L];
 
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 R R ${\href{/padicField/5.4.0.1}{4} }^{4}$ R ${\href{/padicField/11.4.0.1}{4} }^{4}$ ${\href{/padicField/13.4.0.1}{4} }^{4}$ ${\href{/padicField/17.2.0.1}{2} }^{8}$ ${\href{/padicField/19.4.0.1}{4} }^{4}$ ${\href{/padicField/23.2.0.1}{2} }^{8}$ ${\href{/padicField/29.4.0.1}{4} }^{4}$ ${\href{/padicField/31.2.0.1}{2} }^{8}$ ${\href{/padicField/37.4.0.1}{4} }^{4}$ ${\href{/padicField/41.2.0.1}{2} }^{8}$ ${\href{/padicField/43.4.0.1}{4} }^{4}$ ${\href{/padicField/47.2.0.1}{2} }^{8}$ ${\href{/padicField/53.4.0.1}{4} }^{4}$ ${\href{/padicField/59.4.0.1}{4} }^{4}$

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

# to obtain a list of $[e_i,f_i]$ for the factorization of the ideal $p\mathcal{O}_K$ for $p=7$ in Sage:
 
p = 7; [(e, pr.norm().valuation(p)) for pr,e in K.factor(p)]
 
\\ to obtain a list of $[e_i,f_i]$ for the factorization of the ideal $p\mathcal{O}_K$ for $p=7$ in Pari:
 
p = 7; pfac = idealprimedec(K, p); vector(length(pfac), j, [pfac[j][3], pfac[j][4]])
 
// to obtain a list of $[e_i,f_i]$ for the factorization of the ideal $p\mathcal{O}_K$ for $p=7 in Magma:
 
p := 7; [<pr[2], Valuation(Norm(pr[1]), p)> : pr in Factorization(p*Integers(K))];
 
# to obtain a list of $[e_i,f_i]$ for the factorization of the ideal $p\mathcal{O}_K$ 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 2.8.24.9$x^{8} + 8 x^{6} + 14 x^{4} + 4 x^{2} + 8 x + 30$$8$$1$$24$$C_4\times C_2$$[2, 3, 4]$
2.8.24.9$x^{8} + 8 x^{6} + 14 x^{4} + 4 x^{2} + 8 x + 30$$8$$1$$24$$C_4\times C_2$$[2, 3, 4]$
\(3\) Copy content Toggle raw display 3.8.4.1$x^{8} + 4 x^{7} + 16 x^{6} + 36 x^{5} + 94 x^{4} + 116 x^{3} + 144 x^{2} + 36 x + 229$$2$$4$$4$$C_4\times C_2$$[\ ]_{2}^{4}$
3.8.4.1$x^{8} + 4 x^{7} + 16 x^{6} + 36 x^{5} + 94 x^{4} + 116 x^{3} + 144 x^{2} + 36 x + 229$$2$$4$$4$$C_4\times C_2$$[\ ]_{2}^{4}$
\(7\) Copy content Toggle raw display 7.4.2.1$x^{4} + 12 x^{3} + 56 x^{2} + 120 x + 268$$2$$2$$2$$C_2^2$$[\ ]_{2}^{2}$
7.4.2.1$x^{4} + 12 x^{3} + 56 x^{2} + 120 x + 268$$2$$2$$2$$C_2^2$$[\ ]_{2}^{2}$
7.4.2.1$x^{4} + 12 x^{3} + 56 x^{2} + 120 x + 268$$2$$2$$2$$C_2^2$$[\ ]_{2}^{2}$
7.4.2.1$x^{4} + 12 x^{3} + 56 x^{2} + 120 x + 268$$2$$2$$2$$C_2^2$$[\ ]_{2}^{2}$