Properties

Label 2.2.8.56b1.426
Base \(\Q_{2}\)
Degree \(16\)
e \(8\)
f \(2\)
c \(56\)
Galois group $C_2^5.\SD_{16}$ (as 16T955)

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Defining polynomial

$( x^{2} + x + 1 )^{8} + 8 ( x^{2} + x + 1 )^{7} + 4 ( x^{2} + x + 1 )^{6} + \left(8 x + 4\right) ( x^{2} + x + 1 )^{5} + 4 x ( x^{2} + x + 1 )^{4} + 8 ( x^{2} + x + 1 )^{3} + 24 x ( x^{2} + x + 1 )^{2} + 8 ( x^{2} + x + 1 ) + 8 x + 2$ Copy content Toggle raw display

Invariants

Base field: $\Q_{2}$
Degree $d$: $16$
Ramification index $e$: $8$
Residue field degree $f$: $2$
Discriminant exponent $c$: $56$
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:$[3, 4, \frac{17}{4}]$
Visible Swan slopes:$[2,3,\frac{13}{4}]$
Means:$\langle1, 2, \frac{21}{8}\rangle$
Rams:$(2, 4, 5)$
Jump set:$[1, 3, 7, 15]$
Roots of unity:$6 = (2^{ 2 } - 1) \cdot 2$

Intermediate fields

$\Q_{2}(\sqrt{5})$, 2.2.2.6a1.4, 2.2.4.22a1.80

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
Relative Eisenstein polynomial: \( x^{8} + 8 t x^{7} + 8 x^{5} + 4 t x^{4} + \left(8 t + 8\right) x^{2} + 16 t x + 8 t + 2 \) $\ \in\Q_{2}(t)[x]$ Copy content Toggle raw display

Ramification polygon

Residual polynomials:$z^4 + 1$,$z^2 + 1$,$z + 1$
Associated inertia:$1$,$1$,$1$
Indices of inseparability:$[21, 16, 8, 0]$

Invariants of the Galois closure

Galois degree: $512$
Galois group: $C_2^5.\SD_{16}$ (as 16T955)
Inertia group: Intransitive group isomorphic to $C_2^3.C_4^2$
Wild inertia group: $C_2^3.C_4^2$
Galois unramified degree: $4$
Galois tame degree: $1$
Galois Artin slopes: $[2, 3, 3, \frac{7}{2}, 4, 4, \frac{17}{4}]$
Galois Swan slopes: $[1,2,2,\frac{5}{2},3,3,\frac{13}{4}]$
Galois mean slope: $4.0$
Galois splitting model: $x^{16} - 28 x^{14} + 238 x^{12} - 240 x^{11} - 856 x^{10} + 2280 x^{9} + 95 x^{8} - 6720 x^{7} + 4864 x^{6} + 7400 x^{5} - 9242 x^{4} - 1280 x^{3} + 6812 x^{2} - 4040 x + 671$ Copy content Toggle raw display