Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Linking Microscopic Reversibility to Macroscopic Irreversibility,
  Emphasizing the Role of Deterministic Thermostats and Simple Examples, At and
  Away From Equilibrium   Molecular Dynamics and Statistical Mechanics make possible a particle-based
understanding of Thermodynamics and Hydrodynamics, including the fascinating
Loschmidt contradiction between time-reversible atomistic mechanics and the
time-irreversible thermodynamic dissipation incorporated into macroscopic fluid
and solid mechanics.

37
The categories of this paper are: supr-con
16
The categories of this paper are: stat
28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
12
The categories of this paper are: nucl-th
35
The categories of this paper are: mtrl-th
1
The categories of this paper are: cs
6
The categories of this paper are: astro-ph
25
The categories of this paper are: patt-sol
3
The categories of this paper are: physics
0
The categories of this paper are: hep-ph
13
The categories of this paper are: quant-ph
2
The categories of this paper are: math
31
The categories of this paper are: ao-sci