Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: On the motivation and foundation of Natural Time Analysis: Useful
  remarks
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
2
The categories of this paper are: math
18
The categories of this paper are: econ
8
The categories of this paper are: hep-ex
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
15
The categories of this paper are: nucl-ex
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
34
The categories of this paper are: chem-ph
13
The categories of this paper are: quant-ph
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol