Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Random walks in random environments   Random walks in random environments (RWRE's) have been a source of surprising
phenomena and challenging problems since they began to be studied in the 70's.
Hitting times and, more recently, certain regeneration structures, have played
a major role in our understanding of RWRE's. We review these and provide some
hints on current research directions and challenges.

10
The categories of this paper are: q-bio
3
The categories of this paper are: physics
9
The categories of this paper are: nlin
0
The categories of this paper are: hep-ph
31
The categories of this paper are: ao-sci
24
The categories of this paper are: dg-ga
37
The categories of this paper are: supr-con
13
The categories of this paper are: quant-ph
18
The categories of this paper are: econ
1
The categories of this paper are: cs
36
The categories of this paper are: cmp-lg
33
The categories of this paper are: plasm-ph
35
The categories of this paper are: mtrl-th
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
6
The categories of this paper are: astro-ph