Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inverse Scattering Problem for Vector Fields and the Cauchy Problem for
  the Heavenly Equation   We solve the inverse scattering problem for multidimensional vector fields
and we use this result to construct the formal solution of the Cauchy problem
for the second heavenly equation of Plebanski, a scalar nonlinear partial
differential equation in four dimensions relevant in General Relativity, which
arises from the commutation of multidimensional Hamiltonian vector fields.

18
The categories of this paper are: econ
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
3
The categories of this paper are: physics
14
The categories of this paper are: math-ph
0
The categories of this paper are: hep-ph
34
The categories of this paper are: chem-ph
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
31
The categories of this paper are: ao-sci
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
11
The categories of this paper are: hep-lat
32
The categories of this paper are: atom-ph