$p$-adic field 2.9.2.18a20.1

• Label: 2.9.2.18a20.1
• Base: \(\Q_{2}\)
• Degree: \(18\)
• e: \(2\)
• f: \(9\)
• c: \(18\)
• Galois group: $C_2\wr C_9$ (as 18T460)

Defining polynomial

$( x^{9} + x^{4} + 1 )^{2} + \left(2 x^{7} + 2 x^{4} + 2 x^{3} + 2 x + 2\right) ( x^{9} + x^{4} + 1 ) + 2$

Invariants

Base field:	$\Q_{2}$
Degree $d$:	$18$
Ramification index $e$:	$2$
Residue field degree $f$:	$9$
Discriminant exponent $c$:	$18$
Discriminant root field:	$\Q_{2}(\sqrt{-5})$
Root number:	$-i$
$\Aut(K/\Q_{2})$:	$C_2$
This field is not Galois over $\Q_{2}.$
Visible Artin slopes:	$[2]$
Visible Swan slopes:	$[1]$
Means:	$\langle\frac{1}{2}\rangle$
Rams:	$(1)$
Jump set:	$[1, 3]$
Roots of unity:	$1022 = (2^{ 9 } - 1) \cdot 2$

Intermediate fields

2.3.1.0a1.1, 2.9.1.0a1.1

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

Canonical tower

Unramified subfield:	2.9.1.0a1.1 $\cong \Q_{2}(t)$ where $t$ is a root of \( x^{9} + x^{4} + 1 \)
Relative Eisenstein polynomial:	\( x^{2} + \left(2 t^{7} + 2 t^{4} + 2 t^{3} + 2 t + 2\right) x + 6 \) $\ \in\Q_{2}(t)[x]$

Ramification polygon

Residual polynomials:	$z + (t^8 + t^7 + t^5 + t^4 + t^3 + t^2 + t + 1)$
Associated inertia:	$1$
Indices of inseparability:	$[1, 0]$

Invariants of the Galois closure

Galois degree:	$4608$
Galois group:	$C_2\wr C_9$ (as 18T460)
Inertia group:	Intransitive group isomorphic to $C_2^9$
Wild inertia group:	$C_2^9$
Galois unramified degree:	$9$
Galois tame degree:	$1$
Galois Artin slopes:	$[2, 2, 2, 2, 2, 2, 2, 2, 2]$
Galois Swan slopes:	$[1,1,1,1,1,1,1,1,1]$
Galois mean slope:	$1.99609375$
Galois splitting model:	$x^{18} - 27 x^{16} + 153 x^{14} + 1323 x^{12} - 14418 x^{10} + 20169 x^{8} + 116640 x^{6} - 286497 x^{4} + 183708 x^{2} - 19683$