Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Evidence for Heterotic - Type I String Duality   A study is made of the implications of heterotic string $T$-duality and
extended gauge symmetry for the conjectured equivalence of heterotic and Type I
superstrings. While at first sight heterotic string world-sheet dynamics
appears to conflict with Type I perturbation theory, a closer look shows that
Type I perturbation theory ``miraculously'' breaks down, in some cases via
novel mechanisms, whenever the heterotic string has massless particles not
present in Type I perturbation theory. This strongly suggests that the two
theories actually are equivalent. As further evidence in the same direction, we
show that the Dirichlet one-brane of type I string theory has the same
world-sheet structure as the heterotic string.

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The categories of this paper are: supr-con
16
The categories of this paper are: stat
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
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The categories of this paper are: cmp-lg
2
The categories of this paper are: math
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
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The categories of this paper are: ao-sci
13
The categories of this paper are: quant-ph
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The categories of this paper are: econ
0
The categories of this paper are: hep-ph
5
The categories of this paper are: gr-qc
25
The categories of this paper are: patt-sol