Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The fundamental group of Galois cover of the surface ${\mathbb T} \times
  {\mathbb T}$   This is the final paper in a series of four, concerning the surface $T \times
T$ embedded in $\mathbb{CP}^8$, where $T$ is a the one dimensional torus. In
this paper we compute the fundamental group of the Galois cover of the surface
with respect to a generic projection onto $\mathbb{CP}^2$, and show that it is
nilpotent of class 3. This is the first time such a group is presented as the
fundamental group of a Galois cover of a surface.

35
The categories of this paper are: mtrl-th
27
The categories of this paper are: comp-gas
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
19
The categories of this paper are: eess
28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
9
The categories of this paper are: nlin
25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th