Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Existence of solutions of integral equations defined in unbounded
  domains via spectral theory   In this work we study integral equations defined on the whole real line.
Using a suitable Banach space, we look for solutions which satisfy some certain
kind of asymptotic behavior. We will consider spectral theory in order to find
fixed points of the integral operator.

29
The categories of this paper are: funct-an
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
33
The categories of this paper are: plasm-ph
26
The categories of this paper are: bayes-an
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
19
The categories of this paper are: eess
31
The categories of this paper are: ao-sci
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
22
The categories of this paper are: chao-dyn
27
The categories of this paper are: comp-gas
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con