Properties

Label 2.2.4.16a1.1
Base \(\Q_{2}\)
Degree \(8\)
e \(4\)
f \(2\)
c \(16\)
Galois group $S_4$ (as 8T14)

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Defining polynomial

Copy content comment:Define the p-adic field
 
Copy content sage:Prec = 100 # Default precision of 100 Q2 = Qp(2, Prec); x = polygen(QQ) L.<t> = Q2.extension(x^2 + x + 1) K.<a> = L.extension(x^4 + 4*x + 2)
 
Copy content magma:Prec := 100; // Default precision of 100 Q2 := pAdicField(2, Prec); K := LocalField(Q2, Polynomial(Q2, [7, 8, 14, 16, 19, 16, 10, 4, 1]));
 

$( x^{2} + x + 1 )^{4} + 4 ( x^{2} + x + 1 ) + 2$ Copy content Toggle raw display

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

Invariants

Base field: $\Q_{2}$
Copy content comment:Base field Qp
 
Copy content sage:K.base()
 
Copy content magma:Q2;
 
Degree $d$: $8$
Copy content comment:Degree over Qp
 
Copy content sage:K.absolute_degree()
 
Copy content magma:Degree(K);
 
Ramification index $e$:$4$
Copy content comment:Ramification index
 
Copy content sage:K.absolute_e()
 
Copy content magma:RamificationIndex(K);
 
Residue field degree $f$:$2$
Copy content comment:Residue field degree (Inertia degree)
 
Copy content sage:K.absolute_f()
 
Copy content magma:InertiaDegree(K);
 
Discriminant exponent $c$:$16$
Copy content comment:Discriminant exponent
 
Copy content magma:Valuation(Discriminant(K));
 
Discriminant root field:$\Q_{2}$
Root number: $1$
$\Aut(K/\Q_{2})$: $C_2$
This field is not Galois over $\Q_{2}.$
Visible Artin slopes:$[\frac{8}{3}, \frac{8}{3}]$
Visible Swan slopes:$[\frac{5}{3},\frac{5}{3}]$
Means:$\langle\frac{5}{6}, \frac{5}{4}\rangle$
Rams:$(\frac{5}{3}, \frac{5}{3})$
Jump set:$[1, 3, 7]$
Roots of unity:$6 = (2^{ 2 } - 1) \cdot 2$
Copy content comment:Roots of unity
 
Copy content sage:len(K.roots_of_unity())
 

Intermediate fields

$\Q_{2}(\sqrt{5})$, 2.1.4.8a1.1

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

Canonical tower

Unramified subfield:$\Q_{2}(\sqrt{5})$ $\cong \Q_{2}(t)$ where $t$ is a root of \( x^{2} + x + 1 \) Copy content Toggle raw display
Copy content comment:Maximal unramified subextension
 
Copy content sage:K.maximal_unramified_subextension()
 
Relative Eisenstein polynomial: \( x^{4} + 4 x + 2 \) $\ \in\Q_{2}(t)[x]$ Copy content Toggle raw display

Ramification polygon

Residual polynomials:$z + 1$
Associated inertia:$1$
Indices of inseparability:$[5, 4, 0]$

Invariants of the Galois closure

Galois degree: $24$
Galois group: $S_4$ (as 8T14)
Inertia group: Intransitive group isomorphic to $A_4$
Wild inertia group: $C_2^2$
Galois unramified degree: $2$
Galois tame degree: $3$
Galois Artin slopes: $[\frac{8}{3}, \frac{8}{3}]$
Galois Swan slopes: $[\frac{5}{3},\frac{5}{3}]$
Galois mean slope: $2.1666666666666665$
Galois splitting model:$x^{8} - 6 x^{6} - 8 x^{5} + 9 x^{4} + 24 x^{3} + 22 x^{2} + 12 x + 3$