Properties

Label 2.2.8.50b1.320
Base \(\Q_{2}\)
Degree \(16\)
e \(8\)
f \(2\)
c \(50\)
Galois group $C_2^4.D_8$ (as 16T703)

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Defining polynomial

$( x^{2} + x + 1 )^{8} + 8 x ( x^{2} + x + 1 )^{7} + 4 ( x^{2} + x + 1 )^{6} + 8 ( x^{2} + x + 1 )^{5} + 2 ( x^{2} + x + 1 )^{4} + 8 x ( x^{2} + x + 1 )^{3} + 4 ( x^{2} + x + 1 )^{2} + 16 ( x^{2} + x + 1 ) + 2$ Copy content Toggle raw display

Invariants

Base field: $\Q_{2}$
Degree $d$: $16$
Ramification index $e$: $8$
Residue field degree $f$: $2$
Discriminant exponent $c$: $50$
Discriminant root field: $\Q_{2}(\sqrt{5})$
Root number: $1$
$\Aut(K/\Q_{2})$: $C_2$
This field is not Galois over $\Q_{2}.$
Visible Artin slopes:$[2, 3, \frac{17}{4}]$
Visible Swan slopes:$[1,2,\frac{13}{4}]$
Means:$\langle\frac{1}{2}, \frac{5}{4}, \frac{9}{4}\rangle$
Rams:$(1, 3, 8)$
Jump set:$[1, 7, 15, 23]$
Roots of unity:$12 = (2^{ 2 } - 1) \cdot 2^{ 2 }$

Intermediate fields

$\Q_{2}(\sqrt{5})$, $\Q_{2}(\sqrt{-1})$, $\Q_{2}(\sqrt{-5})$, 2.2.2.4a1.1, 2.2.2.6a1.3 x2, 2.1.4.8b1.3 x2, 2.2.4.16b1.4

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: \( x^{8} + 8 t x^{7} + 4 x^{6} + 2 x^{4} + 8 t x^{3} + \left(16 t + 4\right) x^{2} + 2 \) $\ \in\Q_{2}(t)[x]$ 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:$[18, 10, 4, 0]$

Invariants of the Galois closure

Galois degree: $256$
Galois group: $C_2^4.D_8$ (as 16T703)
Inertia group: Intransitive group isomorphic to $C_2^4:D_4$
Wild inertia group: $C_2^4:D_4$
Galois unramified degree: $2$
Galois tame degree: $1$
Galois Artin slopes: $[2, 2, 3, \frac{7}{2}, \frac{7}{2}, 4, \frac{17}{4}]$
Galois Swan slopes: $[1,1,2,\frac{5}{2},\frac{5}{2},3,\frac{13}{4}]$
Galois mean slope: $3.921875$
Galois splitting model: $x^{16} - 16 x^{14} + 124 x^{12} - 560 x^{10} + 1560 x^{8} - 2400 x^{6} + 1800 x^{4} + 500$ Copy content Toggle raw display