Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Galactic Stellar Populations   The history of the formation and evolution of the Milky Way Galaxy is found
in the spatial distribution, kinematics, age and chemical abundance
distributions of long-lived stars. From this fossil record one can in principle
extract the star formation histories of different components, their chemical
evolution, the stellar Initial Mass Function, the merging history -- what
merged and when did it merge? -- and compare with theoretical models.
Observations are driving models, and we live in exciting times.

9
The categories of this paper are: nlin
21
The categories of this paper are: adap-org
31
The categories of this paper are: ao-sci
8
The categories of this paper are: hep-ex
5
The categories of this paper are: gr-qc
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
26
The categories of this paper are: bayes-an
4
The categories of this paper are: cond-mat
11
The categories of this paper are: hep-lat
22
The categories of this paper are: chao-dyn
23
The categories of this paper are: solv-int
17
The categories of this paper are: q-fin
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
13
The categories of this paper are: quant-ph