Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On Unification of RR Couplings   We consider the couplings of RR fields with open string sector for
$Dp$-${\overline{Dp}}$ backgrounds of various $p$. Proposed approach, based on
the approximation of the open string algebra by the algebra of differential
operators, provides the unified description of these couplings and their
interrelations.

26
The categories of this paper are: bayes-an
12
The categories of this paper are: nucl-th
34
The categories of this paper are: chem-ph
33
The categories of this paper are: plasm-ph
27
The categories of this paper are: comp-gas
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
37
The categories of this paper are: supr-con
29
The categories of this paper are: funct-an
13
The categories of this paper are: quant-ph
32
The categories of this paper are: atom-ph
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
28
The categories of this paper are: alg-geom
16
The categories of this paper are: stat