Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Clifford boundary conditions: a simple direct-sum evaluation of Madelung
  constants
6
The categories of this paper are: astro-ph
23
The categories of this paper are: solv-int
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
28
The categories of this paper are: alg-geom
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
16
The categories of this paper are: stat
27
The categories of this paper are: comp-gas
19
The categories of this paper are: eess
2
The categories of this paper are: math
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph