Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: The Continuous Time Random Walk, still trendy: Fifty-year history, state
  of art, and outlook   In this issue we demonstrate the very inspiring role of the continuous-time
random walk (CTRW) formalism and its numerous modifications thanks to their
flexibility and various applications as well its promising perspectives in
different fields of knowledge. A short review of significant achievements and
possibilities is given, however, still far from completeness.

8
The categories of this paper are: hep-ex
21
The categories of this paper are: adap-org
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
7
The categories of this paper are: hep-th
22
The categories of this paper are: chao-dyn
10
The categories of this paper are: q-bio
18
The categories of this paper are: econ
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
16
The categories of this paper are: stat
35
The categories of this paper are: mtrl-th
36
The categories of this paper are: cmp-lg
23
The categories of this paper are: solv-int
29
The categories of this paper are: funct-an