Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Bethe-Salpeter Equation -- The Origins   This article was originally written for scholarpedia.org. It describes the
origins and related background of Bethe-Salpeter equation.

11
The categories of this paper are: hep-lat
30
The categories of this paper are: q-alg
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
18
The categories of this paper are: econ
32
The categories of this paper are: atom-ph
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
23
The categories of this paper are: solv-int
28
The categories of this paper are: alg-geom
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
15
The categories of this paper are: nucl-ex