Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An Introduction to Non-perturbative String Theory   In this review I discuss some basic aspects of non-perturbative string
theory. The topics include test of duality symmetries based on the analysis of
the low energy effective action and the spectrum of BPS states, relationship
between different duality symmetries, an introduction to M- and F-theories,
black hole entropy in string theory, and Matrix theory.

33
The categories of this paper are: plasm-ph
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
13
The categories of this paper are: quant-ph
10
The categories of this paper are: q-bio
24
The categories of this paper are: dg-ga
34
The categories of this paper are: chem-ph