All Questions
Tagged with local-fields galois-cohomology
6 questions with no upvoted or accepted answers
8
votes
0
answers
317
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Finding a cyclic cubic extension of a field
Let $K$ be a field and let $E/K$ be a Galois extension of degree 6 with $\text{Gal}(E/K) = S_3$, the symmetric group on 3 letters. Pick two different transpositions $s_1, s_2$ in $S_3$ (hence $s_1s_2$ ...
7
votes
0
answers
470
views
Explicit $H^2(K, \mu) = Q/Z$?
In the development of local class field theory, a very fundamental theorem is that, for every local field $K$ of characteristic zero,
$H^2(K, \mu) \cong \mathbb{Q}/\mathbb{Z}$. $(*)$
Neukirch et al. ...
4
votes
0
answers
143
views
Unramified Galois cohomology
Let $k$ be a local field with absolute Galois group $\Gamma_k$, inertia subgroup $I_k \subset \Gamma_k$, and residue field $\mathbb{F}$. Let $M$ be a finite Galois module over $k$.
The unramified ...
3
votes
0
answers
141
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Cohomology of local fields in positive characteristic
It is well-known from local class field theory that the Brauer group $\text{Br}(k)$ of a local field $k$ gets killed as you pass to sufficiently large extensions of $k$. In particular, $\text{Br}(L)(p)...
3
votes
0
answers
128
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Galois cohomology with coefficients in the integers of the Lubin-Tate extension
Let $K$ be a $p$-adic local field, and $L$ the Lubin-Tate extension obtained from $K$ by attaching roots of some Lubin-Tate formal $\mathcal{O}_{K}$-module with $Gal(L/K) \simeq \mathcal{O}_{K}^{\...
2
votes
0
answers
60
views
Galois Cohomology mod 2 of iterated Laurent series
Let $k$ be an algebraically closed field of characteristic different from two.
For $n\geq 1$, set $F_n=k((X_1))\cdots ((X_n))$, and let $F=\displaystyle\bigcup_{n\geq 1}F_n$.
If $I=\{i_1,\ldots,i_m\}$...