Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the group of separable quadratic algebras and stacks   The aim of this paper is to study the group of isomorphism classes of torsors
of finite flat group schemes of rank 2 over a commutative ring $R$. This, in
particular, generalises the group of quadratic algebras (free or projective),
which is especially well studied. Our approach however, yields new results even
in this case.

7
The categories of this paper are: hep-th
37
The categories of this paper are: supr-con
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
36
The categories of this paper are: cmp-lg
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
5
The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
13
The categories of this paper are: quant-ph