Properties

Label 21.3.714...224.1
Degree $21$
Signature $[3, 9]$
Discriminant $-7.147\times 10^{27}$
Root discriminant \(21.20\)
Ramified primes $2,3$
Class number $1$ (GRH)
Class group trivial (GRH)
Galois group $\PGL(2,7)$ (as 21T20)

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Show commands: Magma / Oscar / PariGP / SageMath

Normalized defining polynomial

sage: x = polygen(QQ); K.<a> = NumberField(x^21 - 3*x^20 - 4*x^19 + 16*x^18 - 9*x^17 - 33*x^16 + 52*x^15 + 12*x^14 - 136*x^13 + 96*x^12 + 180*x^11 - 260*x^10 - 144*x^9 + 312*x^8 + 44*x^7 - 220*x^6 + 15*x^5 + 59*x^4 - 16*x^3 + 36*x^2 - 31*x + 1)
 
gp: K = bnfinit(y^21 - 3*y^20 - 4*y^19 + 16*y^18 - 9*y^17 - 33*y^16 + 52*y^15 + 12*y^14 - 136*y^13 + 96*y^12 + 180*y^11 - 260*y^10 - 144*y^9 + 312*y^8 + 44*y^7 - 220*y^6 + 15*y^5 + 59*y^4 - 16*y^3 + 36*y^2 - 31*y + 1, 1)
 
magma: R<x> := PolynomialRing(Rationals()); K<a> := NumberField(x^21 - 3*x^20 - 4*x^19 + 16*x^18 - 9*x^17 - 33*x^16 + 52*x^15 + 12*x^14 - 136*x^13 + 96*x^12 + 180*x^11 - 260*x^10 - 144*x^9 + 312*x^8 + 44*x^7 - 220*x^6 + 15*x^5 + 59*x^4 - 16*x^3 + 36*x^2 - 31*x + 1);
 
oscar: Qx, x = PolynomialRing(QQ); K, a = NumberField(x^21 - 3*x^20 - 4*x^19 + 16*x^18 - 9*x^17 - 33*x^16 + 52*x^15 + 12*x^14 - 136*x^13 + 96*x^12 + 180*x^11 - 260*x^10 - 144*x^9 + 312*x^8 + 44*x^7 - 220*x^6 + 15*x^5 + 59*x^4 - 16*x^3 + 36*x^2 - 31*x + 1)
 

\( x^{21} - 3 x^{20} - 4 x^{19} + 16 x^{18} - 9 x^{17} - 33 x^{16} + 52 x^{15} + 12 x^{14} - 136 x^{13} + \cdots + 1 \) Copy content Toggle raw display

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

Invariants

Degree:  $21$
sage: K.degree()
 
gp: poldegree(K.pol)
 
magma: Degree(K);
 
oscar: degree(K)
 
Signature:  $[3, 9]$
sage: K.signature()
 
gp: K.sign
 
magma: Signature(K);
 
oscar: signature(K)
 
Discriminant:   \(-7146646609494406531041460224\) \(\medspace = -\,2^{64}\cdot 3^{18}\) 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:  \(21.20\)
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:  $2^{29/8}3^{6/7}\approx 31.63696468726565$
Ramified primes:   \(2\), \(3\) 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:  \(\Q(\sqrt{-1}) \)
$\card{ \Aut(K/\Q) }$:  $1$
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 \(a\))

$1$, $a$, $a^{2}$, $a^{3}$, $a^{4}$, $a^{5}$, $a^{6}$, $a^{7}$, $\frac{1}{2}a^{8}-\frac{1}{2}$, $\frac{1}{2}a^{9}-\frac{1}{2}a$, $\frac{1}{2}a^{10}-\frac{1}{2}a^{2}$, $\frac{1}{2}a^{11}-\frac{1}{2}a^{3}$, $\frac{1}{4}a^{12}-\frac{1}{4}a^{8}+\frac{1}{4}a^{4}-\frac{1}{4}$, $\frac{1}{4}a^{13}-\frac{1}{4}a^{9}+\frac{1}{4}a^{5}-\frac{1}{4}a$, $\frac{1}{8}a^{14}-\frac{1}{8}a^{12}+\frac{1}{8}a^{10}-\frac{1}{8}a^{8}+\frac{1}{8}a^{6}-\frac{1}{8}a^{4}+\frac{1}{8}a^{2}-\frac{1}{8}$, $\frac{1}{8}a^{15}-\frac{1}{8}a^{13}+\frac{1}{8}a^{11}-\frac{1}{8}a^{9}+\frac{1}{8}a^{7}-\frac{1}{8}a^{5}+\frac{1}{8}a^{3}-\frac{1}{8}a$, $\frac{1}{8}a^{16}-\frac{1}{8}$, $\frac{1}{64}a^{17}-\frac{3}{64}a^{16}+\frac{1}{32}a^{15}-\frac{1}{32}a^{14}+\frac{1}{16}a^{13}+\frac{7}{32}a^{11}+\frac{5}{32}a^{10}-\frac{1}{4}a^{9}-\frac{1}{16}a^{8}-\frac{15}{32}a^{7}-\frac{9}{32}a^{6}+\frac{3}{16}a^{5}-\frac{3}{8}a^{4}+\frac{11}{32}a^{3}+\frac{1}{32}a^{2}-\frac{1}{64}a+\frac{15}{64}$, $\frac{1}{64}a^{18}+\frac{1}{64}a^{16}-\frac{1}{16}a^{15}-\frac{1}{32}a^{14}+\frac{1}{16}a^{13}-\frac{1}{32}a^{12}+\frac{3}{16}a^{11}+\frac{7}{32}a^{10}+\frac{1}{16}a^{9}+\frac{3}{32}a^{8}+\frac{3}{16}a^{7}+\frac{11}{32}a^{6}+\frac{1}{16}a^{5}-\frac{1}{32}a^{4}+\frac{7}{16}a^{3}+\frac{5}{64}a^{2}+\frac{1}{16}a+\frac{21}{64}$, $\frac{1}{128}a^{19}-\frac{1}{128}a^{18}-\frac{1}{128}a^{17}-\frac{7}{128}a^{16}+\frac{3}{64}a^{15}+\frac{1}{64}a^{14}+\frac{5}{64}a^{13}-\frac{5}{64}a^{12}+\frac{7}{64}a^{11}-\frac{3}{64}a^{10}-\frac{3}{64}a^{9}-\frac{5}{64}a^{8}-\frac{25}{64}a^{7}-\frac{27}{64}a^{6}+\frac{29}{64}a^{5}+\frac{27}{64}a^{4}+\frac{37}{128}a^{3}+\frac{19}{128}a^{2}-\frac{21}{128}a-\frac{3}{128}$, $\frac{1}{1157298870656}a^{20}-\frac{1048673419}{1157298870656}a^{19}-\frac{779216257}{1157298870656}a^{18}+\frac{2580505063}{1157298870656}a^{17}-\frac{27905486493}{578649435328}a^{16}-\frac{9131520381}{578649435328}a^{15}+\frac{8596105857}{578649435328}a^{14}+\frac{11920676885}{578649435328}a^{13}+\frac{3984972003}{578649435328}a^{12}-\frac{50090446817}{578649435328}a^{11}+\frac{128354582921}{578649435328}a^{10}+\frac{66215511389}{578649435328}a^{9}+\frac{2597510291}{578649435328}a^{8}-\frac{59552884241}{578649435328}a^{7}+\frac{83339962201}{578649435328}a^{6}-\frac{243029498667}{578649435328}a^{5}-\frac{330362936963}{1157298870656}a^{4}-\frac{191820525839}{1157298870656}a^{3}-\frac{513957271741}{1157298870656}a^{2}-\frac{401219358285}{1157298870656}a-\frac{53116372489}{144662358832}$ Copy content Toggle raw display

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

Monogenic:  No
Index:  Not computed
Inessential primes:  $2$

Class group and class number

Trivial group, which has order $1$ (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:  $11$
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:   $\frac{129427364769}{1157298870656}a^{20}-\frac{158973451327}{578649435328}a^{19}-\frac{351863426395}{578649435328}a^{18}+\frac{213741308075}{144662358832}a^{17}-\frac{147170050183}{1157298870656}a^{16}-\frac{139141792923}{36165589708}a^{15}+\frac{133303594185}{36165589708}a^{14}+\frac{1065014444933}{289324717664}a^{13}-\frac{3862091276047}{289324717664}a^{12}+\frac{448956981469}{144662358832}a^{11}+\frac{1651205609303}{72331179416}a^{10}-\frac{4704181620609}{289324717664}a^{9}-\frac{7740895406949}{289324717664}a^{8}+\frac{750934815771}{36165589708}a^{7}+\frac{2688136179979}{144662358832}a^{6}-\frac{4202981530531}{289324717664}a^{5}-\frac{8711131285301}{1157298870656}a^{4}+\frac{2051237676699}{578649435328}a^{3}+\frac{375446281071}{578649435328}a^{2}+\frac{1194438179365}{289324717664}a-\frac{748174762069}{1157298870656}$, $\frac{83285702587}{578649435328}a^{20}-\frac{471299973371}{1157298870656}a^{19}-\frac{731066570167}{1157298870656}a^{18}+\frac{2508421152449}{1157298870656}a^{17}-\frac{1162863783073}{1157298870656}a^{16}-\frac{2769265833775}{578649435328}a^{15}+\frac{3859091009665}{578649435328}a^{14}+\frac{1424314263809}{578649435328}a^{13}-\frac{10898906902719}{578649435328}a^{12}+\frac{6343032261785}{578649435328}a^{11}+\frac{15341905437881}{578649435328}a^{10}-\frac{18913369187827}{578649435328}a^{9}-\frac{14048401201219}{578649435328}a^{8}+\frac{23118287100389}{578649435328}a^{7}+\frac{6319577821861}{578649435328}a^{6}-\frac{16834079217695}{578649435328}a^{5}-\frac{262813125261}{289324717664}a^{4}+\frac{9502578675477}{1157298870656}a^{3}-\frac{2070075445679}{1157298870656}a^{2}+\frac{5355361971721}{1157298870656}a-\frac{3708346015125}{1157298870656}$, $\frac{16089452013}{578649435328}a^{20}-\frac{17548746351}{289324717664}a^{19}-\frac{21856414013}{144662358832}a^{18}+\frac{169017638937}{578649435328}a^{17}-\frac{5242378001}{144662358832}a^{16}-\frac{247523631651}{289324717664}a^{15}+\frac{194248956357}{289324717664}a^{14}+\frac{14750844585}{18082794854}a^{13}-\frac{27158031835}{9041397427}a^{12}+\frac{58938698615}{289324717664}a^{11}+\frac{1391455292931}{289324717664}a^{10}-\frac{435926288707}{144662358832}a^{9}-\frac{915434320323}{144662358832}a^{8}+\frac{1187941773949}{289324717664}a^{7}+\frac{979254130849}{289324717664}a^{6}-\frac{374257690087}{72331179416}a^{5}-\frac{884382196413}{578649435328}a^{4}+\frac{376067881649}{144662358832}a^{3}-\frac{161403691203}{289324717664}a^{2}-\frac{661133074917}{578649435328}a+\frac{4901810997}{9041397427}$, $\frac{596854485}{578649435328}a^{20}+\frac{54738701309}{1157298870656}a^{19}-\frac{86242213247}{1157298870656}a^{18}-\frac{372447403255}{1157298870656}a^{17}+\frac{284018345067}{1157298870656}a^{16}+\frac{107102601553}{578649435328}a^{15}-\frac{672805223615}{578649435328}a^{14}+\frac{7284441729}{578649435328}a^{13}+\frac{799000775169}{578649435328}a^{12}-\frac{1809294548679}{578649435328}a^{11}-\frac{1664278463639}{578649435328}a^{10}+\frac{3411423357325}{578649435328}a^{9}+\frac{1236688604861}{578649435328}a^{8}-\frac{5569920789019}{578649435328}a^{7}-\frac{2939011913259}{578649435328}a^{6}+\frac{2985599791105}{578649435328}a^{5}+\frac{121812064719}{144662358832}a^{4}-\frac{3024670686115}{1157298870656}a^{3}-\frac{515121661671}{1157298870656}a^{2}-\frac{1938633392639}{1157298870656}a+\frac{698342925247}{1157298870656}$, $\frac{175280861911}{1157298870656}a^{20}-\frac{474345335353}{1157298870656}a^{19}-\frac{842727929861}{1157298870656}a^{18}+\frac{2545962503109}{1157298870656}a^{17}-\frac{200299827153}{289324717664}a^{16}-\frac{2963218437203}{578649435328}a^{15}+\frac{3676671911565}{578649435328}a^{14}+\frac{2075541487619}{578649435328}a^{13}-\frac{11162835527285}{578649435328}a^{12}+\frac{5290248244545}{578649435328}a^{11}+\frac{17010187305589}{578649435328}a^{10}-\frac{17399443180533}{578649435328}a^{9}-\frac{16924064124733}{578649435328}a^{8}+\frac{21301089653217}{578649435328}a^{7}+\frac{9141061001485}{578649435328}a^{6}-\frac{14444410115453}{578649435328}a^{5}-\frac{3611798241913}{1157298870656}a^{4}+\frac{6744952422995}{1157298870656}a^{3}-\frac{2045579758673}{1157298870656}a^{2}+\frac{5565662366129}{1157298870656}a-\frac{1770253298615}{578649435328}$, $\frac{150829193581}{1157298870656}a^{20}-\frac{27030032205}{72331179416}a^{19}-\frac{155989835767}{289324717664}a^{18}+\frac{1113139812617}{578649435328}a^{17}-\frac{1213518456829}{1157298870656}a^{16}-\frac{1158648299527}{289324717664}a^{15}+\frac{1750259688207}{289324717664}a^{14}+\frac{54258396817}{36165589708}a^{13}-\frac{2367945883271}{144662358832}a^{12}+\frac{3143193015583}{289324717664}a^{11}+\frac{6217762521895}{289324717664}a^{10}-\frac{4227533373839}{144662358832}a^{9}-\frac{1268707592147}{72331179416}a^{8}+\frac{9675108434837}{289324717664}a^{7}+\frac{1317275909569}{289324717664}a^{6}-\frac{815099808675}{36165589708}a^{5}+\frac{3364234441443}{1157298870656}a^{4}+\frac{1248927194331}{289324717664}a^{3}-\frac{79071756327}{36165589708}a^{2}+\frac{2966272951331}{578649435328}a-\frac{4418522544091}{1157298870656}$, $\frac{3359282503}{144662358832}a^{20}-\frac{66654576101}{1157298870656}a^{19}-\frac{151532555141}{1157298870656}a^{18}+\frac{338261364355}{1157298870656}a^{17}+\frac{87861959335}{1157298870656}a^{16}-\frac{426144093597}{578649435328}a^{15}+\frac{276532168247}{578649435328}a^{14}+\frac{649253579135}{578649435328}a^{13}-\frac{1331297534653}{578649435328}a^{12}-\frac{59851945197}{578649435328}a^{11}+\frac{2957563553807}{578649435328}a^{10}-\frac{638342218053}{578649435328}a^{9}-\frac{4048852935457}{578649435328}a^{8}+\frac{1024368592895}{578649435328}a^{7}+\frac{4303583226683}{578649435328}a^{6}+\frac{581903411775}{578649435328}a^{5}-\frac{2196665477569}{578649435328}a^{4}-\frac{2259113796893}{1157298870656}a^{3}+\frac{3071011350219}{1157298870656}a^{2}+\frac{2215155328163}{1157298870656}a+\frac{87945479831}{1157298870656}$, $\frac{48263755047}{578649435328}a^{20}-\frac{263242917151}{1157298870656}a^{19}-\frac{442129772493}{1157298870656}a^{18}+\frac{1402219910317}{1157298870656}a^{17}-\frac{623484547327}{1157298870656}a^{16}-\frac{1587754015015}{578649435328}a^{15}+\frac{2137511821311}{578649435328}a^{14}+\frac{764403052657}{578649435328}a^{13}-\frac{6092355161441}{578649435328}a^{12}+\frac{3401115447985}{578649435328}a^{11}+\frac{8398381718951}{578649435328}a^{10}-\frac{10321679352147}{578649435328}a^{9}-\frac{7516351947837}{578649435328}a^{8}+\frac{11460785465485}{578649435328}a^{7}+\frac{3257201988475}{578649435328}a^{6}-\frac{7872140844655}{578649435328}a^{5}-\frac{123910516381}{72331179416}a^{4}+\frac{1704601063209}{1157298870656}a^{3}+\frac{263322172723}{1157298870656}a^{2}+\frac{4197240082333}{1157298870656}a-\frac{2685712297355}{1157298870656}$, $\frac{39316738907}{289324717664}a^{20}-\frac{209022228451}{578649435328}a^{19}-\frac{390454918837}{578649435328}a^{18}+\frac{572530078401}{289324717664}a^{17}-\frac{162322627653}{289324717664}a^{16}-\frac{698664710397}{144662358832}a^{15}+\frac{828641734339}{144662358832}a^{14}+\frac{1066380406143}{289324717664}a^{13}-\frac{5231200325489}{289324717664}a^{12}+\frac{542450349773}{72331179416}a^{11}+\frac{2054130684897}{72331179416}a^{10}-\frac{8204460044927}{289324717664}a^{9}-\frac{8504501869023}{289324717664}a^{8}+\frac{5423249163725}{144662358832}a^{7}+\frac{2273792544077}{144662358832}a^{6}-\frac{8858615353949}{289324717664}a^{5}-\frac{67969170667}{36165589708}a^{4}+\frac{7018655491867}{578649435328}a^{3}-\frac{2668113096115}{578649435328}a^{2}+\frac{10269039948}{9041397427}a-\frac{61247657997}{144662358832}$, $\frac{55984860469}{1157298870656}a^{20}-\frac{8847417263}{72331179416}a^{19}-\frac{78366406115}{289324717664}a^{18}+\frac{94586205003}{144662358832}a^{17}+\frac{94267975449}{1157298870656}a^{16}-\frac{58879832119}{36165589708}a^{15}+\frac{47495410085}{36165589708}a^{14}+\frac{296535077493}{144662358832}a^{13}-\frac{767776510765}{144662358832}a^{12}+\frac{3111103409}{9041397427}a^{11}+\frac{1549189302641}{144662358832}a^{10}-\frac{649646319205}{144662358832}a^{9}-\frac{2116162921503}{144662358832}a^{8}+\frac{436543789581}{72331179416}a^{7}+\frac{1933482851545}{144662358832}a^{6}-\frac{429233354709}{144662358832}a^{5}-\frac{6966646160741}{1157298870656}a^{4}-\frac{1472824249}{18082794854}a^{3}+\frac{79756044051}{289324717664}a^{2}+\frac{127959377307}{72331179416}a-\frac{145589222425}{1157298870656}$, $\frac{99512973441}{1157298870656}a^{20}-\frac{302722324513}{1157298870656}a^{19}-\frac{376806790615}{1157298870656}a^{18}+\frac{1606020582627}{1157298870656}a^{17}-\frac{507199169487}{578649435328}a^{16}-\frac{1648988284889}{578649435328}a^{15}+\frac{2636552399185}{578649435328}a^{14}+\frac{472755449139}{578649435328}a^{13}-\frac{6877599018147}{578649435328}a^{12}+\frac{4981376767183}{578649435328}a^{11}+\frac{8757130585205}{578649435328}a^{10}-\frac{13600648825681}{578649435328}a^{9}-\frac{6961348706863}{578649435328}a^{8}+\frac{16452205934651}{578649435328}a^{7}+\frac{2221781600529}{578649435328}a^{6}-\frac{12097830568133}{578649435328}a^{5}+\frac{20480587745}{1157298870656}a^{4}+\frac{5765033739335}{1157298870656}a^{3}-\frac{893216980847}{1157298870656}a^{2}+\frac{3482133593755}{1157298870656}a-\frac{426409143305}{144662358832}$ 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:  \( 3668230.07566 \) (assuming GRH)
sage: K.regulator()
 
gp: K.reg
 
magma: Regulator(K);
 
oscar: regulator(K)
 

Class number formula

\[ \begin{aligned}\lim_{s\to 1} (s-1)\zeta_K(s) =\mathstrut & \frac{2^{r_1}\cdot (2\pi)^{r_2}\cdot R\cdot h}{w\cdot\sqrt{|D|}}\cr \approx\mathstrut &\frac{2^{3}\cdot(2\pi)^{9}\cdot 3668230.07566 \cdot 1}{2\cdot\sqrt{7146646609494406531041460224}}\cr\approx \mathstrut & 2.64901379622 \end{aligned}\] (assuming GRH)

# self-contained SageMath code snippet to compute the analytic class number formula
 
x = polygen(QQ); K.<a> = NumberField(x^21 - 3*x^20 - 4*x^19 + 16*x^18 - 9*x^17 - 33*x^16 + 52*x^15 + 12*x^14 - 136*x^13 + 96*x^12 + 180*x^11 - 260*x^10 - 144*x^9 + 312*x^8 + 44*x^7 - 220*x^6 + 15*x^5 + 59*x^4 - 16*x^3 + 36*x^2 - 31*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^21 - 3*x^20 - 4*x^19 + 16*x^18 - 9*x^17 - 33*x^16 + 52*x^15 + 12*x^14 - 136*x^13 + 96*x^12 + 180*x^11 - 260*x^10 - 144*x^9 + 312*x^8 + 44*x^7 - 220*x^6 + 15*x^5 + 59*x^4 - 16*x^3 + 36*x^2 - 31*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^21 - 3*x^20 - 4*x^19 + 16*x^18 - 9*x^17 - 33*x^16 + 52*x^15 + 12*x^14 - 136*x^13 + 96*x^12 + 180*x^11 - 260*x^10 - 144*x^9 + 312*x^8 + 44*x^7 - 220*x^6 + 15*x^5 + 59*x^4 - 16*x^3 + 36*x^2 - 31*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^21 - 3*x^20 - 4*x^19 + 16*x^18 - 9*x^17 - 33*x^16 + 52*x^15 + 12*x^14 - 136*x^13 + 96*x^12 + 180*x^11 - 260*x^10 - 144*x^9 + 312*x^8 + 44*x^7 - 220*x^6 + 15*x^5 + 59*x^4 - 16*x^3 + 36*x^2 - 31*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

$\PGL(2,7)$ (as 21T20):

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 non-solvable group of order 336
The 9 conjugacy class representatives for $\PGL(2,7)$
Character table for $\PGL(2,7)$

Intermediate fields

The extension is primitive: there are no intermediate fields between this field and $\Q$.
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

Degree 8 sibling: 8.2.195689447424.8
Degree 14 sibling: data not computed
Degree 16 sibling: data not computed
Degree 24 sibling: data not computed
Degree 28 siblings: data not computed
Degree 42 siblings: data not computed
Minimal sibling: 8.2.195689447424.8

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 ${\href{/padicField/5.7.0.1}{7} }^{3}$ ${\href{/padicField/7.6.0.1}{6} }^{3}{,}\,{\href{/padicField/7.3.0.1}{3} }$ ${\href{/padicField/11.8.0.1}{8} }^{2}{,}\,{\href{/padicField/11.4.0.1}{4} }{,}\,{\href{/padicField/11.1.0.1}{1} }$ ${\href{/padicField/13.3.0.1}{3} }^{7}$ ${\href{/padicField/17.3.0.1}{3} }^{7}$ ${\href{/padicField/19.6.0.1}{6} }^{3}{,}\,{\href{/padicField/19.3.0.1}{3} }$ ${\href{/padicField/23.8.0.1}{8} }^{2}{,}\,{\href{/padicField/23.4.0.1}{4} }{,}\,{\href{/padicField/23.1.0.1}{1} }$ ${\href{/padicField/29.3.0.1}{3} }^{7}$ ${\href{/padicField/31.8.0.1}{8} }^{2}{,}\,{\href{/padicField/31.4.0.1}{4} }{,}\,{\href{/padicField/31.1.0.1}{1} }$ ${\href{/padicField/37.7.0.1}{7} }^{3}$ ${\href{/padicField/41.4.0.1}{4} }^{4}{,}\,{\href{/padicField/41.2.0.1}{2} }^{2}{,}\,{\href{/padicField/41.1.0.1}{1} }$ ${\href{/padicField/43.8.0.1}{8} }^{2}{,}\,{\href{/padicField/43.4.0.1}{4} }{,}\,{\href{/padicField/43.1.0.1}{1} }$ ${\href{/padicField/47.6.0.1}{6} }^{3}{,}\,{\href{/padicField/47.3.0.1}{3} }$ ${\href{/padicField/53.4.0.1}{4} }^{4}{,}\,{\href{/padicField/53.2.0.1}{2} }^{2}{,}\,{\href{/padicField/53.1.0.1}{1} }$ ${\href{/padicField/59.8.0.1}{8} }^{2}{,}\,{\href{/padicField/59.4.0.1}{4} }{,}\,{\href{/padicField/59.1.0.1}{1} }$

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

# 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 $\Q_{2}$$x + 1$$1$$1$$0$Trivial$[\ ]$
2.4.9.3$x^{4} + 4 x^{3} + 2 x^{2} + 2$$4$$1$$9$$D_{4}$$[2, 3, 7/2]$
2.8.28.65$x^{8} + 8 x^{7} + 12 x^{6} + 8 x^{5} + 16 x^{2} + 10$$8$$1$$28$$D_{8}$$[2, 3, 7/2, 9/2]$
2.8.27.41$x^{8} + 8 x^{5} + 2 x^{4} + 8 x^{2} + 2$$8$$1$$27$$D_{8}$$[2, 3, 7/2, 9/2]$
\(3\) Copy content Toggle raw display Deg $21$$7$$3$$18$