Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Amplification of light in a glass ball suspended within a gainy medium   We discuss total internal reflection (TIR) from an interface between glass
and active gaseous media and propose an experiment for strong light
amplification.

28
The categories of this paper are: alg-geom
23
The categories of this paper are: solv-int
16
The categories of this paper are: stat
13
The categories of this paper are: quant-ph
7
The categories of this paper are: hep-th
8
The categories of this paper are: hep-ex
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
6
The categories of this paper are: astro-ph
36
The categories of this paper are: cmp-lg
1
The categories of this paper are: cs
27
The categories of this paper are: comp-gas