Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A GAS OF D-INSTANTONS   A D-instanton is a space-time event associated with world-sheet boundaries
that contributes non-perturbative effects of order $e^{-const/\kappa}$ to
closed-string amplitudes. Some properties of a gas of D-instantons are
discussed in this paper.

8
The categories of this paper are: hep-ex
4
The categories of this paper are: cond-mat
29
The categories of this paper are: funct-an
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
3
The categories of this paper are: physics
21
The categories of this paper are: adap-org
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
10
The categories of this paper are: q-bio
22
The categories of this paper are: chao-dyn
26
The categories of this paper are: bayes-an