Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Inhomogeneous Spatially Dispersive Electromagnetic Media   Two key types of inhomogeneous spatially dispersive media are described, both
based on a spatially dispersive generalisation of the single resonance model of
permittivity. The boundary conditions for two such media with different
properties are investigated using Lagrangian and distributional methods. Wave
packet solutions to Maxwell's equations, where the permittivity varies and is
periodic in the medium, are then found.

7
The categories of this paper are: hep-th
2
The categories of this paper are: math
14
The categories of this paper are: math-ph
1
The categories of this paper are: cs
25
The categories of this paper are: patt-sol
12
The categories of this paper are: nucl-th
36
The categories of this paper are: cmp-lg
8
The categories of this paper are: hep-ex
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
24
The categories of this paper are: dg-ga
16
The categories of this paper are: stat
37
The categories of this paper are: supr-con
20
The categories of this paper are: acc-phys
33
The categories of this paper are: plasm-ph
32
The categories of this paper are: atom-ph