Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Matter-Antimatter Asymmetry in the Universe and an Arrow for Time   An overview is given of theoretical attempts to explain the matter-antimatter
asymmetry in the Universe, emphasizing particularly leptogenesis and the
Affleck-Dine mechanism.

16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
35
The categories of this paper are: mtrl-th
18
The categories of this paper are: econ
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
4
The categories of this paper are: cond-mat
30
The categories of this paper are: q-alg
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
3
The categories of this paper are: physics