Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: An improved approximation algorithm for k-median problem using a new
  factor-revealing LP   The k-median problem is a well-known strongly NP-hard combinatorial
optimization problem of both theoretical and practical significance. The
previous best approximation ratio for this problem is 2.611+\epsilon (Bryka et
al. 2014) based on an (1, 1.95238219) bi-factor approximation algorithm for the
classical facility location problem (FLP). This work offers an improved
algorithm with an approximation ratio 2.592 +\epsilon based on a new (1,
1.93910094) bi-factor approximation algorithm for the FLP.

22
The categories of this paper are: chao-dyn
36
The categories of this paper are: cmp-lg
21
The categories of this paper are: adap-org
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
6
The categories of this paper are: astro-ph
13
The categories of this paper are: quant-ph
27
The categories of this paper are: comp-gas
35
The categories of this paper are: mtrl-th
34
The categories of this paper are: chem-ph
11
The categories of this paper are: hep-lat
14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
30
The categories of this paper are: q-alg