Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Greedy algorithm for stochastic matching is a 2-approximation   Motivated by applications in online dating and kidney exchange, the
stochastic matching problem was introduced by Chen, Immorlica, Karlin, Mahdian
and Rudra (2009). They have proven a 4-approximation of a simple greedy
strategy, but conjectured that it is in fact a 2-approximation. In this paper
we confirm this hypothesis.

28
The categories of this paper are: alg-geom
30
The categories of this paper are: q-alg
23
The categories of this paper are: solv-int
26
The categories of this paper are: bayes-an
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
8
The categories of this paper are: hep-ex
35
The categories of this paper are: mtrl-th
6
The categories of this paper are: astro-ph
16
The categories of this paper are: stat
29
The categories of this paper are: funct-an
21
The categories of this paper are: adap-org
25
The categories of this paper are: patt-sol
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin