Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Galois Theory, discriminants and torsion subgroups of elliptic curves   We find a tight relationship between the torsion subgroup and the image of
the mod 2 Galois representation associated to an elliptic curve defined over
the rationals. This is shown using some characterizations for the squareness of
the discriminant of the elliptic curve.

15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
6
The categories of this paper are: astro-ph
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
24
The categories of this paper are: dg-ga
0
The categories of this paper are: hep-ph
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg