Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Gravitational Microlensing   This review forms the microlensing part of the 33rd Saas-Fee Advanced Course
"Gravitational Lensing: Strong, Weak & Micro'', which was held in April 2003 in
Les Diablerets. It contains an introduction to the lensing effects of single
and binary stars and it summarizes the state-of-the-art of microlensing
observations and prospects at the time of the meeting. Stellar microlensing as
well as quasar microlensing are covered.

30
The categories of this paper are: q-alg
29
The categories of this paper are: funct-an
7
The categories of this paper are: hep-th
15
The categories of this paper are: nucl-ex
11
The categories of this paper are: hep-lat
0
The categories of this paper are: hep-ph
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
9
The categories of this paper are: nlin
31
The categories of this paper are: ao-sci
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
17
The categories of this paper are: q-fin
5
The categories of this paper are: gr-qc
27
The categories of this paper are: comp-gas
37
The categories of this paper are: supr-con