Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dispersionless Hierarchies, Hamilton-Jacobi Theory and Twistor
  Correspondences   The dispersionless KP and Toda hierarchies possess an underlying twistorial
structure. A twistorial approach is partly implemented by the method of
Riemann-Hilbert problem. This is however still short of clarifying geometric
ingredients of twistor theory, such as twistor lines and twistor surfaces. A
more geometric approach can be developed in a Hamilton-Jacobi formalism of
Gibbons and Kodama. AMS Subject Classifiation (1991): 35Q20, 58F07,70H99

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The categories of this paper are: physics
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The categories of this paper are: nucl-ex
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The categories of this paper are: ao-sci
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The categories of this paper are: dg-ga
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The categories of this paper are: funct-an
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The categories of this paper are: atom-ph
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The categories of this paper are: cmp-lg
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The categories of this paper are: cs
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The categories of this paper are: chem-ph
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The categories of this paper are: math-ph
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The categories of this paper are: comp-gas
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The categories of this paper are: nucl-th
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The categories of this paper are: eess
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The categories of this paper are: q-alg
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The categories of this paper are: cond-mat
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The categories of this paper are: acc-phys