Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Approximation Algorithms for Probabilistic Graphs   We study the k-median and k-center problems in probabilistic graphs. We
analyze the hardness of these problems, and propose several algorithms with
improved approximation ratios compared with the existing proposals.

9
The categories of this paper are: nlin
5
The categories of this paper are: gr-qc
10
The categories of this paper are: q-bio
8
The categories of this paper are: hep-ex
18
The categories of this paper are: econ
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
15
The categories of this paper are: nucl-ex
32
The categories of this paper are: atom-ph
28
The categories of this paper are: alg-geom
6
The categories of this paper are: astro-ph
7
The categories of this paper are: hep-th
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat