Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Spline-backfitted kernel smoothing of nonlinear additive autoregression
  model
21
The categories of this paper are: adap-org
37
The categories of this paper are: supr-con
5
The categories of this paper are: gr-qc
15
The categories of this paper are: nucl-ex
7
The categories of this paper are: hep-th
18
The categories of this paper are: econ
31
The categories of this paper are: ao-sci
6
The categories of this paper are: astro-ph
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
12
The categories of this paper are: nucl-th