Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A proposal for regularly updated review/survey articles: "Perpetual
  Reviews"   We advocate the publication of review/survey articles that will be updated
regularly, both in traditional journals and novel venues. We call these
"perpetual reviews." This idea naturally builds on the dissemination and
archival capabilities present in the modern internet, and indeed perpetual
reviews exist already in some forms. Perpetual review articles allow authors to
maintain over time the relevance of non-research scholarship that requires a
significant investment of effort. Further, such reviews published in a purely
electronic format without space constraints can also permit more pedagogical
scholarship and clearer treatment of technical issues that remain obscure in a
brief treatment.

30
The categories of this paper are: q-alg
34
The categories of this paper are: chem-ph
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
4
The categories of this paper are: cond-mat
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
20
The categories of this paper are: acc-phys
11
The categories of this paper are: hep-lat
33
The categories of this paper are: plasm-ph
23
The categories of this paper are: solv-int
7
The categories of this paper are: hep-th
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
10
The categories of this paper are: q-bio
3
The categories of this paper are: physics