Defining polynomial
\(x^{8} + 8 x^{7} + 32 x^{6} + 82 x^{5} + 148 x^{4} + 184 x^{3} + 137 x^{2} + 44 x + 5\) |
Invariants
Base field: | $\Q_{2}$ |
Degree $d$: | $8$ |
Ramification exponent $e$: | $2$ |
Residue field degree $f$: | $4$ |
Discriminant exponent $c$: | $8$ |
Discriminant root field: | $\Q_{2}$ |
Root number: | $1$ |
$\card{ \Gal(K/\Q_{ 2 }) }$: | $8$ |
This field is Galois and abelian over $\Q_{2}.$ | |
Visible slopes: | $[2]$ |
Intermediate fields
$\Q_{2}(\sqrt{5})$, $\Q_{2}(\sqrt{-1})$, $\Q_{2}(\sqrt{-5})$, 2.4.0.1, 2.4.4.1, 2.4.4.2 |
Fields in the database are given up to isomorphism. Isomorphic intermediate fields are shown with their multiplicities.
Unramified/totally ramified tower
Unramified subfield: | 2.4.0.1 $\cong \Q_{2}(t)$ where $t$ is a root of \( x^{4} + x + 1 \) |
Relative Eisenstein polynomial: | \( x^{2} + 2 x + 2 \) $\ \in\Q_{2}(t)[x]$ |
Ramification polygon
Residual polynomials: | $z + 1$ |
Associated inertia: | $1$ |
Indices of inseparability: | $[1, 0]$ |
Invariants of the Galois closure
Galois group: | $C_2\times C_4$ (as 8T2) |
Inertia group: | Intransitive group isomorphic to $C_2$ |
Wild inertia group: | $C_2$ |
Unramified degree: | $4$ |
Tame degree: | $1$ |
Wild slopes: | $[2]$ |
Galois mean slope: | $1$ |
Galois splitting model: | $x^{8} - x^{6} + x^{4} - x^{2} + 1$ |