Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: String Expansion as Large N Expansion of Gauge Theories   We consider string perturbative expansion in the presence of D-branes
imbedded in orbifolded space-time. In the regime where the string coupling is
weak and $\alpha'\to 0$, the string perturbative expansion coincides with `t
Hooft's large N expansion. We specifically concentrate on theories with d=4 and
${\cal N}=0,1,2,4$, and use world-sheet orbifold techniques to prove vanishing
theorems for the field theory beta functions to all orders in perturbation
theory in the large N limit. This is in accord with recent predictions.

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The categories of this paper are: cmp-lg
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The categories of this paper are: supr-con
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The categories of this paper are: hep-lat
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The categories of this paper are: math
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The categories of this paper are: mtrl-th
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The categories of this paper are: dg-ga
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The categories of this paper are: math-ph
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The categories of this paper are: atom-ph
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The categories of this paper are: q-alg
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The categories of this paper are: comp-gas
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The categories of this paper are: plasm-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: q-fin
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The categories of this paper are: chao-dyn
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The categories of this paper are: ao-sci