Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Groupes fondamentaux des varietes de dimension 3 et algebres
  d'operateurs   We provide a geometric characterization of manifolds of dimension 3 with
fundamental groups of which all conjugacy classes except 1 are infinite, namely
of which the von Neumann algebras are factors of type $II_1$: they are
essentially the 3-manifolds with infinite fundamental groups on which there
does not exist any Seifert fibration.
  Otherwise said and more precisely, let $M$ be a compact connected 3-manifold
and let $\Gamma$ be its fundamental group, supposed to be infinite and with at
least one finite conjugacy class besides 1. If $M$ is orientable, then $\Gamma$
is the fundamental group of a Seifert manifold; if $M$ is not orientable, then
$\Gamma$ is the fundamental group of a Seifert manifold modulo $\Bbb P$ in the
sense of Heil and Whitten \cite{HeWh--94}.
  We make heavy use of results on 3-manifolds, as well classical results (as
can be found in the books of Hempel, Jaco, and Shalen), as more recent ones
(solution of the Seifert fibred space conjecture).

20
The categories of this paper are: acc-phys
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
34
The categories of this paper are: chem-ph
29
The categories of this paper are: funct-an
11
The categories of this paper are: hep-lat
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
6
The categories of this paper are: astro-ph
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
21
The categories of this paper are: adap-org
10
The categories of this paper are: q-bio