Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A Probability Density Function for Google's stocks   It is an approach to introduce the forward Kolmogorov equation as an
interesting natural ingredient in studying the evolution of the market stock
prices.

7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
4
The categories of this paper are: cond-mat
23
The categories of this paper are: solv-int
30
The categories of this paper are: q-alg
28
The categories of this paper are: alg-geom
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
19
The categories of this paper are: eess
26
The categories of this paper are: bayes-an
36
The categories of this paper are: cmp-lg