Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Hierarchy of Superstrings   We construct a hierarchy of supersymmetric string theories by showing that
the general N-extended superstrings may be viewed as a special class of the
(N+1)-extended superstrings. As a side result, we find a twisted (N+2)
superconformal algebra realized in the N-extended string.

13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
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The categories of this paper are: eess
11
The categories of this paper are: hep-lat
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The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
4
The categories of this paper are: cond-mat
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
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The categories of this paper are: dg-ga
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The categories of this paper are: cmp-lg
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The categories of this paper are: chao-dyn
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The categories of this paper are: q-alg
25
The categories of this paper are: patt-sol
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph