Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On two-dimensional nonlocal Venttsel' problems in piecewise smooth
  domains   We establish the regularity results for solutions of nonlocal Venttsel'
problems in polygonal and piecewise smooth two-dimensional domains.

6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
3
The categories of this paper are: physics
31
The categories of this paper are: ao-sci
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
1
The categories of this paper are: cs
4
The categories of this paper are: cond-mat
34
The categories of this paper are: chem-ph
14
The categories of this paper are: math-ph
30
The categories of this paper are: q-alg