Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: A time-reversible quantum causal model
30
The categories of this paper are: q-alg
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
32
The categories of this paper are: atom-ph
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
18
The categories of this paper are: econ
2
The categories of this paper are: math
3
The categories of this paper are: physics
35
The categories of this paper are: mtrl-th
14
The categories of this paper are: math-ph