Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the existence of a torsor structure for Galois covers   Let $R$ be a complete discrete valuation ring with residue characteristic
$p>0$. In this note we give an example of a Galois cover $f:Y\to X$ between
flat and normal formal $R$-schemes of finite type which is \'etale above the
generic fibre of $X$ such that the special fibre of $Y$ is reduced and such
that $f$ doesn't have the structure of a torsor under a finite and flat $R$
group scheme. In the example $R$ has equal characteristic $p$ and the Galois
group of the cover is cyclic of order $p^2$. In the example the formal scheme
$X$ is affine and can be choosen to be even smooth.

20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
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The categories of this paper are: funct-an
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
10
The categories of this paper are: q-bio
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con