Instruct: Identify the main and secondary category of Arxiv papers based on the titles
Query: Hardening in a Time--Evolving Stellar Background: Hyper--Velocity Stars,
  Orbital Decay and Prediction for Lisa
10
The categories of this paper are: q-bio
23
The categories of this paper are: solv-int
2
The categories of this paper are: math
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
28
The categories of this paper are: alg-geom
5
The categories of this paper are: gr-qc
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
4
The categories of this paper are: cond-mat
16
The categories of this paper are: stat
11
The categories of this paper are: hep-lat