Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On Brauer groups of double covers of ruled surfaces   Let X be a smooth double cover of a geometrically ruled surface defined over
a separably closed field of characteristic different from 2. The main result of
this paper is a finite presentation of the 2-torsion in the Brauer group of X
with generators given by central simple algebras over the function field of X
and relations coming from the N\'eron-Severi group of X. In particular, the
result gives a central simple algebra representative for the unique nontrivial
Brauer class on any Enriques surface. An example demonstrating the applications
to the study of rational points is given.

37
The categories of this paper are: supr-con
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
21
The categories of this paper are: adap-org
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
31
The categories of this paper are: ao-sci
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
24
The categories of this paper are: dg-ga
28
The categories of this paper are: alg-geom
19
The categories of this paper are: eess
0
The categories of this paper are: hep-ph