Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A remark on the definitions of viscosity solutions for the
  integro-differential equations with L{\'e}vy operators   The equivalence of three different definitions of viscosity solutions for the
integro-differential equation with the L{\'e}vy operator is shown in this
paper. The key is Lemma 2.1, in which we construct a sequence of the
approximating test functions.

16
The categories of this paper are: stat
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
33
The categories of this paper are: plasm-ph
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The categories of this paper are: chem-ph
3
The categories of this paper are: physics
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
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The categories of this paper are: comp-gas
15
The categories of this paper are: nucl-ex
1
The categories of this paper are: cs
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The categories of this paper are: q-fin
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The categories of this paper are: nucl-th
4
The categories of this paper are: cond-mat
26
The categories of this paper are: bayes-an
8
The categories of this paper are: hep-ex