Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Exact risk improvement of bandwidth selectors for kernel density
  estimation with directional data
11
The categories of this paper are: hep-lat
12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
3
The categories of this paper are: physics
25
The categories of this paper are: patt-sol
24
The categories of this paper are: dg-ga
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
2
The categories of this paper are: math
20
The categories of this paper are: acc-phys
26
The categories of this paper are: bayes-an
22
The categories of this paper are: chao-dyn
1
The categories of this paper are: cs