Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Exact thresholds and instanton effects in D=3 string theories   Three-dimensional string theories with 16 supersymmetries are believed to
possess a non-perturbative U-duality symmetry $SO(8,24,\Zint)$. By
covariantizing the heterotic one-loop amplitude under U-duality, we propose an
exact expression for the $(\partial \phi)^4$ amplitude, that reproduces known
perturbative limits. The weak-coupling expansion in either of the heterotic,
type II or type I descriptions exhibits the well-known instanton effects, plus
new contributions peculiar to three-dimensional theories, including the
Kaluza-Klein 5-brane, for which we extract the summation measure. This letter
is a post-scriptum to hepth/0001083.

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The categories of this paper are: nlin
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The categories of this paper are: eess
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The categories of this paper are: stat
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg
22
The categories of this paper are: chao-dyn
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The categories of this paper are: nucl-th
0
The categories of this paper are: hep-ph
3
The categories of this paper are: physics
10
The categories of this paper are: q-bio
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The categories of this paper are: astro-ph
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The categories of this paper are: bayes-an
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The categories of this paper are: atom-ph
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The categories of this paper are: chem-ph
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The categories of this paper are: dg-ga
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The categories of this paper are: hep-lat