Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Internal observability of the wave equation in tiled domains   We investigate the internal observability of the wave equation with Dirichlet
boundary conditions in tilings. The paper includes a general result relating
internal observability problems in general domains to their tiles, and a
discussion of the case in which the domain is the 30-60-90 triangle.

34
The categories of this paper are: chem-ph
20
The categories of this paper are: acc-phys
28
The categories of this paper are: alg-geom
9
The categories of this paper are: nlin
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
25
The categories of this paper are: patt-sol
32
The categories of this paper are: atom-ph
5
The categories of this paper are: gr-qc
12
The categories of this paper are: nucl-th
37
The categories of this paper are: supr-con
33
The categories of this paper are: plasm-ph
7
The categories of this paper are: hep-th
13
The categories of this paper are: quant-ph
1
The categories of this paper are: cs
0
The categories of this paper are: hep-ph