Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Some global aspects of linear wave equations   This paper surveys a few aspects of the global theory of wave equations. This
material is structured around the contents of a minicourse given by the second
author during the CMI/ETH Summer School on evolution equations during the
Summer of 2008.

12
The categories of this paper are: nucl-th
5
The categories of this paper are: gr-qc
14
The categories of this paper are: math-ph
23
The categories of this paper are: solv-int
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat
27
The categories of this paper are: comp-gas
11
The categories of this paper are: hep-lat
36
The categories of this paper are: cmp-lg
17
The categories of this paper are: q-fin
24
The categories of this paper are: dg-ga
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
30
The categories of this paper are: q-alg
0
The categories of this paper are: hep-ph
37
The categories of this paper are: supr-con