Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Symmetry and transformation of waves in optics and acoustics of crystals   It is show that in group representation by non-traditionally determining by
the Maxwell equations, instead of wave, linear differential operator of
momentous type from the common point of view the transformation of
electromagnetic and ultrasonic radiation as well as the formation of caustics
generation of solitons in crystals is represented. It is established that
forming operator structural constants determine bias current with the connected
charge and group velocity and also optical and acoustic axes of a crystal,
which characterize its wave properties, moreover crystals are classified on
common electromagnetic base. It is discovered that at change of crystal
symmetry and representation of different wave process the problems also take
place, which are similar to others spheres of physics and are constructed on
the same aximatical base.

23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
25
The categories of this paper are: patt-sol
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
2
The categories of this paper are: math
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
34
The categories of this paper are: chem-ph
16
The categories of this paper are: stat
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
19
The categories of this paper are: eess
13
The categories of this paper are: quant-ph
15
The categories of this paper are: nucl-ex
5
The categories of this paper are: gr-qc