Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Linear problems and B\"acklund transformations for the Hirota-Ohta
  system   The auxiliary linear problems are presented for all discretization levels of
the Hirota-Ohta system. The structure of these linear problems coincides
essentially with the structure of Nonlinear Schr\"odinger hierarchy. The
squared eigenfunction constraints are found which relate Hirota-Ohta and
Kulish-Sklyanin vectorial NLS hierarchies.

17
The categories of this paper are: q-fin
6
The categories of this paper are: astro-ph
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The categories of this paper are: econ
3
The categories of this paper are: physics
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
25
The categories of this paper are: patt-sol
10
The categories of this paper are: q-bio
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
0
The categories of this paper are: hep-ph
8
The categories of this paper are: hep-ex
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The categories of this paper are: funct-an
37
The categories of this paper are: supr-con
4
The categories of this paper are: cond-mat
15
The categories of this paper are: nucl-ex