Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The complexity of the Structure and Classification of Dynamical Systems   This is an expository paper about the Borel complexity of structure and
classification theorems. It sorts several classical problems relative to known
benchmarks of complexity. As a corollary various problems proposed by people
such as von Neumann and Smale are shown to be infeasible using inherently
countable information.

9
The categories of this paper are: nlin
10
The categories of this paper are: q-bio
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
31
The categories of this paper are: ao-sci
32
The categories of this paper are: atom-ph
24
The categories of this paper are: dg-ga
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
3
The categories of this paper are: physics
19
The categories of this paper are: eess
23
The categories of this paper are: solv-int
36
The categories of this paper are: cmp-lg
35
The categories of this paper are: mtrl-th
30
The categories of this paper are: q-alg