Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Theory of orthogonality of eigenfunctions of the characteristic
  equations as a method of solution boundary problems for model kinetic
  equations   We consider two classes of linear kinetic equations: with constant collision
frequency and constant mean free path of gas molecules (i.e., frequency of
molecular collisions, proportional to the modulus molecular velocity). Based
homogeneous Riemann boundary value problem with a coefficient equal to the
ratio of the boundary values dispersion function, develops the theory of the
half-space orthogonality of generalized singular eigenfunctions corresponding
characteristic equations, which leads separation of variables. And in this two
boundary value problems of the kinetic theory (diffusion light component of a
binary gas and Kramers problem about isothermal slip) shows the application of
the theory orthogonality eigenfunctions for analytical solutions these tasks.

25
The categories of this paper are: patt-sol
1
The categories of this paper are: cs
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
32
The categories of this paper are: atom-ph
23
The categories of this paper are: solv-int
21
The categories of this paper are: adap-org
13
The categories of this paper are: quant-ph
33
The categories of this paper are: plasm-ph
36
The categories of this paper are: cmp-lg
24
The categories of this paper are: dg-ga
29
The categories of this paper are: funct-an
26
The categories of this paper are: bayes-an
9
The categories of this paper are: nlin
6
The categories of this paper are: astro-ph
4
The categories of this paper are: cond-mat