Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On the sum of two integral squares in certain quadratic fields   In this note, we give a necessary and sufficient condition for determining
which integers can be written as a sum of two integral squares for certain
quadratic fields by using the integral Brauer-manin obstruction (see
\cite{CTX}). The condition is computable and originally from the reciprocity
law.

14
The categories of this paper are: math-ph
13
The categories of this paper are: quant-ph
5
The categories of this paper are: gr-qc
18
The categories of this paper are: econ
9
The categories of this paper are: nlin
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
16
The categories of this paper are: stat
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th