Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the structure of just infinite profinite groups   A profinite group $G$ is just infinite if every closed normal subgroup of $G$
is of finite index. We prove that an infinite profinite group is just infinite
if and only if, for every open subgroup $H$ of $G$, there are only finitely
many open normal subgroups of $G$ not contained in $H$. This extends a result
recently established by Barnea, Gavioli, Jaikin-Zapirain, Monti and Scoppola,
who proved the same characterisation in the case of pro-$p$ groups. We also use
this result to establish a number of features of the general structure of
profinite groups with regard to the just infinite property.

11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
20
The categories of this paper are: acc-phys
8
The categories of this paper are: hep-ex
37
The categories of this paper are: supr-con
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph
21
The categories of this paper are: adap-org
22
The categories of this paper are: chao-dyn
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
6
The categories of this paper are: astro-ph
12
The categories of this paper are: nucl-th
9
The categories of this paper are: nlin
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg