Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Diffraction by an impedance strip I. Reducing diffraction problem to
  Riemann-Hilbert problems   A 2D problem of acoustic wave scattering by a segment bearing impedance
boundary conditions is considered. In the current paper (the first part of a
series of two) some preliminary steps are made, namely, the diffraction problem
is reduced to two matrix Riemann-Hilbert problems with exponential growth of
unknown functions (for the symmetrical part and for the antisymmetrical part).
For this, the Wiener--Hopf problems are formulated, they are reduced to
auxiliary functional problems by applying the embedding formula, and finally
the Riemann-Hilbert problems are formulated by applying the Hurd's method.
  In the second part the Riemann-Hilbert problems will be solved by a novel
method of OE-equation.

35
The categories of this paper are: mtrl-th
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
1
The categories of this paper are: cs
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
28
The categories of this paper are: alg-geom
3
The categories of this paper are: physics
24
The categories of this paper are: dg-ga
14
The categories of this paper are: math-ph
22
The categories of this paper are: chao-dyn
17
The categories of this paper are: q-fin
27
The categories of this paper are: comp-gas
6
The categories of this paper are: astro-ph