Properties

Label 15.1.44543599279432079.1
Degree $15$
Signature $[1, 7]$
Discriminant $-4.454\times 10^{16}$
Root discriminant \(12.88\)
Ramified prime $239$
Class number $1$
Class group trivial
Galois group $D_{15}$ (as 15T2)

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Show commands: Magma / Oscar / PariGP / SageMath

Normalized defining polynomial

sage: x = polygen(QQ); K.<a> = NumberField(x^15 - 4*x^14 + 4*x^13 + 4*x^12 - 5*x^11 - 13*x^10 + 20*x^9 + 4*x^8 - 15*x^7 - 13*x^6 + 27*x^5 - 4*x^4 - 8*x^3 - 2*x^2 + 6*x - 1)
 
gp: K = bnfinit(y^15 - 4*y^14 + 4*y^13 + 4*y^12 - 5*y^11 - 13*y^10 + 20*y^9 + 4*y^8 - 15*y^7 - 13*y^6 + 27*y^5 - 4*y^4 - 8*y^3 - 2*y^2 + 6*y - 1, 1)
 
magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(x^15 - 4*x^14 + 4*x^13 + 4*x^12 - 5*x^11 - 13*x^10 + 20*x^9 + 4*x^8 - 15*x^7 - 13*x^6 + 27*x^5 - 4*x^4 - 8*x^3 - 2*x^2 + 6*x - 1);
 
oscar: Qx, x = PolynomialRing(QQ); K, a = NumberField(x^15 - 4*x^14 + 4*x^13 + 4*x^12 - 5*x^11 - 13*x^10 + 20*x^9 + 4*x^8 - 15*x^7 - 13*x^6 + 27*x^5 - 4*x^4 - 8*x^3 - 2*x^2 + 6*x - 1)
 

\( x^{15} - 4 x^{14} + 4 x^{13} + 4 x^{12} - 5 x^{11} - 13 x^{10} + 20 x^{9} + 4 x^{8} - 15 x^{7} + \cdots - 1 \) Copy content Toggle raw display

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

Invariants

Degree:  $15$
sage: K.degree()
 
gp: poldegree(K.pol)
 
magma: Degree(K);
 
oscar: degree(K)
 
Signature:  $[1, 7]$
sage: K.signature()
 
gp: K.sign
 
magma: Signature(K);
 
oscar: signature(K)
 
Discriminant:   \(-44543599279432079\) \(\medspace = -\,239^{7}\) 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:  \(12.88\)
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:  $239^{1/2}\approx 15.459624833740307$
Ramified primes:   \(239\) 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:  \(\Q(\sqrt{-239}) \)
$\card{ \Aut(K/\Q) }$:  $1$
sage: K.automorphisms()
 
magma: Automorphisms(K);
 
oscar: automorphisms(K)
 
This field is not Galois over $\Q$.
This is not a CM field.

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

$1$, $a$, $a^{2}$, $a^{3}$, $a^{4}$, $a^{5}$, $a^{6}$, $a^{7}$, $a^{8}$, $a^{9}$, $a^{10}$, $a^{11}$, $a^{12}$, $a^{13}$, $\frac{1}{34333}a^{14}-\frac{6031}{34333}a^{13}-\frac{9806}{34333}a^{12}+\frac{13673}{34333}a^{11}-\frac{7976}{34333}a^{10}+\frac{5139}{34333}a^{9}-\frac{4367}{34333}a^{8}-\frac{13498}{34333}a^{7}-\frac{16779}{34333}a^{6}+\frac{16335}{34333}a^{5}+\frac{16026}{34333}a^{4}-\frac{9977}{34333}a^{3}+\frac{752}{1807}a^{2}-\frac{6614}{34333}a+\frac{1971}{34333}$ 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

Trivial group, which has order $1$

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:   $\frac{2825}{34333}a^{14}-\frac{8407}{34333}a^{13}+\frac{4781}{34333}a^{12}+\frac{1600}{34333}a^{11}+\frac{24581}{34333}a^{10}-\frac{39517}{34333}a^{9}-\frac{11228}{34333}a^{8}+\frac{12113}{34333}a^{7}+\frac{81864}{34333}a^{6}-\frac{65843}{34333}a^{5}-\frac{46110}{34333}a^{4}+\frac{2368}{34333}a^{3}+\frac{4789}{1807}a^{2}-\frac{41731}{34333}a-\frac{28204}{34333}$, $\frac{9151}{34333}a^{14}-\frac{16550}{34333}a^{13}-\frac{22577}{34333}a^{12}+\frac{46504}{34333}a^{11}+\frac{72248}{34333}a^{10}-\frac{112220}{34333}a^{9}-\frac{101804}{34333}a^{8}+\frac{147268}{34333}a^{7}+\frac{129879}{34333}a^{6}-\frac{175962}{34333}a^{5}-\frac{119649}{34333}a^{4}+\frac{129252}{34333}a^{3}+\frac{4110}{1807}a^{2}-\frac{29968}{34333}a-\frac{22537}{34333}$, $\frac{4072}{34333}a^{14}-\frac{10137}{34333}a^{13}-\frac{753}{34333}a^{12}+\frac{22663}{34333}a^{11}+\frac{746}{34333}a^{10}-\frac{51455}{34333}a^{9}+\frac{36403}{34333}a^{8}+\frac{37610}{34333}a^{7}-\frac{35751}{34333}a^{6}-\frac{55567}{34333}a^{5}+\frac{59505}{34333}a^{4}-\frac{10405}{34333}a^{3}-\frac{721}{1807}a^{2}-\frac{15136}{34333}a+\frac{26323}{34333}$, $\frac{1179}{34333}a^{14}-\frac{3618}{34333}a^{13}+\frac{8947}{34333}a^{12}-\frac{16043}{34333}a^{11}+\frac{3538}{34333}a^{10}+\frac{16273}{34333}a^{9}+\frac{35590}{34333}a^{8}-\frac{86629}{34333}a^{7}-\frac{6633}{34333}a^{6}+\frac{66818}{34333}a^{5}+\frac{45837}{34333}a^{4}-\frac{123996}{34333}a^{3}+\frac{1178}{1807}a^{2}+\frac{30018}{34333}a+\frac{23498}{34333}$, $\frac{1744}{34333}a^{14}-\frac{12166}{34333}a^{13}+\frac{30503}{34333}a^{12}-\frac{15723}{34333}a^{11}-\frac{39612}{34333}a^{10}+\frac{1503}{34333}a^{9}+\frac{143210}{34333}a^{8}-\frac{91073}{34333}a^{7}-\frac{113859}{34333}a^{6}+\frac{26183}{34333}a^{5}+\frac{208280}{34333}a^{4}-\frac{130389}{34333}a^{3}-\frac{4008}{1807}a^{2}+\frac{1072}{34333}a+\frac{72790}{34333}$, $\frac{4567}{34333}a^{14}-\frac{8511}{34333}a^{13}-\frac{13770}{34333}a^{12}+\frac{27197}{34333}a^{11}+\frac{35254}{34333}a^{10}-\frac{48292}{34333}a^{9}-\frac{65282}{34333}a^{8}+\frac{51035}{34333}a^{7}+\frac{70229}{34333}a^{6}-\frac{37997}{34333}a^{5}-\frac{75880}{34333}a^{4}+\frac{29265}{34333}a^{3}+\frac{2891}{1807}a^{2}+\frac{6902}{34333}a-\frac{28022}{34333}$, $\frac{13063}{34333}a^{14}-\frac{57384}{34333}a^{13}+\frac{69311}{34333}a^{12}+\frac{44466}{34333}a^{11}-\frac{92832}{34333}a^{10}-\frac{161923}{34333}a^{9}+\frac{324322}{34333}a^{8}+\frac{9914}{34333}a^{7}-\frac{242536}{34333}a^{6}-\frac{132822}{34333}a^{5}+\frac{397000}{34333}a^{4}-\frac{104482}{34333}a^{3}-\frac{4897}{1807}a^{2}-\frac{16854}{34333}a+\frac{31756}{34333}$ Copy content Toggle raw display
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:  \( 124.657592501 \)
sage: K.regulator()
 
gp: K.reg
 
magma: Regulator(K);
 
oscar: regulator(K)
 

Class number formula

\[ \begin{aligned}\lim_{s\to 1} (s-1)\zeta_K(s) =\mathstrut & \frac{2^{r_1}\cdot (2\pi)^{r_2}\cdot R\cdot h}{w\cdot\sqrt{|D|}}\cr \approx\mathstrut &\frac{2^{1}\cdot(2\pi)^{7}\cdot 124.657592501 \cdot 1}{2\cdot\sqrt{44543599279432079}}\cr\approx \mathstrut & 0.228341663351 \end{aligned}\]

# self-contained SageMath code snippet to compute the analytic class number formula
 
x = polygen(QQ); K.<a> = NumberField(x^15 - 4*x^14 + 4*x^13 + 4*x^12 - 5*x^11 - 13*x^10 + 20*x^9 + 4*x^8 - 15*x^7 - 13*x^6 + 27*x^5 - 4*x^4 - 8*x^3 - 2*x^2 + 6*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))))
 
# self-contained Pari/GP code snippet to compute the analytic class number formula
 
K = bnfinit(x^15 - 4*x^14 + 4*x^13 + 4*x^12 - 5*x^11 - 13*x^10 + 20*x^9 + 4*x^8 - 15*x^7 - 13*x^6 + 27*x^5 - 4*x^4 - 8*x^3 - 2*x^2 + 6*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)))]
 
/* self-contained Magma code snippet to compute the analytic class number formula */
 
Qx<x> := PolynomialRing(QQ); K<a> := NumberField(x^15 - 4*x^14 + 4*x^13 + 4*x^12 - 5*x^11 - 13*x^10 + 20*x^9 + 4*x^8 - 15*x^7 - 13*x^6 + 27*x^5 - 4*x^4 - 8*x^3 - 2*x^2 + 6*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)));
 
# self-contained Oscar code snippet to compute the analytic class number formula
 
Qx, x = PolynomialRing(QQ); K, a = NumberField(x^15 - 4*x^14 + 4*x^13 + 4*x^12 - 5*x^11 - 13*x^10 + 20*x^9 + 4*x^8 - 15*x^7 - 13*x^6 + 27*x^5 - 4*x^4 - 8*x^3 - 2*x^2 + 6*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

$D_{15}$ (as 15T2):

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)
 
A solvable group of order 30
The 9 conjugacy class representatives for $D_{15}$
Character table for $D_{15}$

Intermediate fields

3.1.239.1, 5.1.57121.1

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]
 

Sibling fields

Galois closure: deg 30
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 $15$ ${\href{/padicField/3.5.0.1}{5} }^{3}$ $15$ ${\href{/padicField/7.2.0.1}{2} }^{7}{,}\,{\href{/padicField/7.1.0.1}{1} }$ $15$ ${\href{/padicField/13.2.0.1}{2} }^{7}{,}\,{\href{/padicField/13.1.0.1}{1} }$ ${\href{/padicField/17.3.0.1}{3} }^{5}$ ${\href{/padicField/19.2.0.1}{2} }^{7}{,}\,{\href{/padicField/19.1.0.1}{1} }$ ${\href{/padicField/23.2.0.1}{2} }^{7}{,}\,{\href{/padicField/23.1.0.1}{1} }$ $15$ $15$ ${\href{/padicField/37.2.0.1}{2} }^{7}{,}\,{\href{/padicField/37.1.0.1}{1} }$ ${\href{/padicField/41.2.0.1}{2} }^{7}{,}\,{\href{/padicField/41.1.0.1}{1} }$ ${\href{/padicField/43.2.0.1}{2} }^{7}{,}\,{\href{/padicField/43.1.0.1}{1} }$ ${\href{/padicField/47.2.0.1}{2} }^{7}{,}\,{\href{/padicField/47.1.0.1}{1} }$ ${\href{/padicField/53.2.0.1}{2} }^{7}{,}\,{\href{/padicField/53.1.0.1}{1} }$ ${\href{/padicField/59.2.0.1}{2} }^{7}{,}\,{\href{/padicField/59.1.0.1}{1} }$

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
\(239\) Copy content Toggle raw display $\Q_{239}$$x$$1$$1$$0$Trivial$[\ ]$
Deg $2$$2$$1$$1$$C_2$$[\ ]_{2}$
Deg $2$$2$$1$$1$$C_2$$[\ ]_{2}$
Deg $2$$2$$1$$1$$C_2$$[\ ]_{2}$
Deg $2$$2$$1$$1$$C_2$$[\ ]_{2}$
Deg $2$$2$$1$$1$$C_2$$[\ ]_{2}$
Deg $2$$2$$1$$1$$C_2$$[\ ]_{2}$
Deg $2$$2$$1$$1$$C_2$$[\ ]_{2}$

Artin representations

Label Dimension Conductor Artin stem field $G$ Ind $\chi(c)$
* 1.1.1t1.a.a$1$ $1$ \(\Q\) $C_1$ $1$ $1$
1.239.2t1.a.a$1$ $ 239 $ \(\Q(\sqrt{-239}) \) $C_2$ (as 2T1) $1$ $-1$
* 2.239.3t2.a.a$2$ $ 239 $ 3.1.239.1 $S_3$ (as 3T2) $1$ $0$
* 2.239.5t2.a.a$2$ $ 239 $ 5.1.57121.1 $D_{5}$ (as 5T2) $1$ $0$
* 2.239.5t2.a.b$2$ $ 239 $ 5.1.57121.1 $D_{5}$ (as 5T2) $1$ $0$
* 2.239.15t2.a.c$2$ $ 239 $ 15.1.44543599279432079.1 $D_{15}$ (as 15T2) $1$ $0$
* 2.239.15t2.a.a$2$ $ 239 $ 15.1.44543599279432079.1 $D_{15}$ (as 15T2) $1$ $0$
* 2.239.15t2.a.b$2$ $ 239 $ 15.1.44543599279432079.1 $D_{15}$ (as 15T2) $1$ $0$
* 2.239.15t2.a.d$2$ $ 239 $ 15.1.44543599279432079.1 $D_{15}$ (as 15T2) $1$ $0$

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 *.