Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Experiments and numerical results on nonlinear vibrations of an
  impacting hertzian contact. Part 1: harmonic excitation
22
The categories of this paper are: chao-dyn
28
The categories of this paper are: alg-geom
32
The categories of this paper are: atom-ph
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
23
The categories of this paper are: solv-int
37
The categories of this paper are: supr-con
6
The categories of this paper are: astro-ph
26
The categories of this paper are: bayes-an
10
The categories of this paper are: q-bio
11
The categories of this paper are: hep-lat
24
The categories of this paper are: dg-ga
7
The categories of this paper are: hep-th
30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph