Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Crystal potentials under invariant periodic boundary conditions at
  infinity   The definiteness of bulk electrostatic potentials in solids under periodic
boundary conditions defined in an invariant manner has been proved in the
general case of triclinic symmetry. Some principal consequences following from
the universal potential correction arising are discussed briefly.

27
The categories of this paper are: comp-gas
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
1
The categories of this paper are: cs
32
The categories of this paper are: atom-ph
34
The categories of this paper are: chem-ph
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
23
The categories of this paper are: solv-int
24
The categories of this paper are: dg-ga
12
The categories of this paper are: nucl-th
17
The categories of this paper are: q-fin
9
The categories of this paper are: nlin
13
The categories of this paper are: quant-ph
6
The categories of this paper are: astro-ph