Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: New Principles for String/Membrane Unification   The target space theory of the N=(2,1) heterotic string may be interpreted as
a theory of gravity coupled to matter in either $1+1$ or $2+1$ dimensions.
Among the target space theories in $1+1$ dimensions are the bosonic, type II,
and heterotic string world sheet field theories in a physical gauge. The $2+1$
dimensional version describes a consistent quantum theory of supermembranes in
$10+1$ dimensions. The unifying framework for all of these vacua is a theory of
$2+2$ dimensional self-dual geometries embedded in $10+2$ dimensions. There are
also indications that the N=(2,1) string describes the strong coupling dynamics
of compactifications of critical string theories to two dimensions, and may
lead to insights about the fundamental degrees of freedom of the theory.

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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: chao-dyn
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The categories of this paper are: nucl-ex
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The categories of this paper are: math
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The categories of this paper are: econ
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The categories of this paper are: hep-lat
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The categories of this paper are: bayes-an
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The categories of this paper are: plasm-ph
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The categories of this paper are: mtrl-th
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The categories of this paper are: adap-org
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The categories of this paper are: atom-ph
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The categories of this paper are: patt-sol
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The categories of this paper are: ao-sci
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The categories of this paper are: cmp-lg
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The categories of this paper are: q-fin