Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Dynamics of two-component electromagnetic and acoustic extremely short
  pulses   The distinctive features of passing the two-component extremely short pulses
through the nonlinear media are discussed. The equations considered describe
the propagation in the two-level anisotropic medium of the electromagnetic
pulses consisting of ordinary and extraordinary components and an evolution of
the transverse-longitudinal acoustic pulses in a crystal containing the
paramagnetic impurities with effective spin S=1/2. The solutions decreasing
exponentially and algebraically are studied.

28
The categories of this paper are: alg-geom
15
The categories of this paper are: nucl-ex
19
The categories of this paper are: eess
35
The categories of this paper are: mtrl-th
29
The categories of this paper are: funct-an
4
The categories of this paper are: cond-mat
8
The categories of this paper are: hep-ex
3
The categories of this paper are: physics
1
The categories of this paper are: cs
31
The categories of this paper are: ao-sci
25
The categories of this paper are: patt-sol
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph
10
The categories of this paper are: q-bio
30
The categories of this paper are: q-alg
2
The categories of this paper are: math