Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: D'Alembert-type solution of the Cauchy problem for a
  Boussinesq-Klein-Gordon equation   In this paper we construct a weakly-nonlinear d'Alembert-type solution of the
Cauchy problem for a Boussinesq-Klein-Gordon equation. Similarly to our earlier
work based on the use of spatial Fourier series, we consider the problem in the
class of periodic functions on an interval of finite length (including the
limiting case of an "infinite" interval with zero boundary conditions), and
work with the equation describing a deviation from the mean value.
  Unlike our earlier paper, here we develop a novel multiple-scales procedure
involving fast characteristic variables and two slow time scales, which allows
us to construct an explicit and compact d'Alembert-type solution of the
nonlinear problem in terms of solutions of two Ostrovsky equations emerging at
the leading order and describing the right- and left-propagating waves.
Validity of the constructed solution follows from our earlier results, and is
illustrated numerically for a number of instructive examples, both for periodic
solutions on a finite interval, and the well-studied scenario for localised
solutions on a large ("infinite") interval.
  Importantly, in all cases the initial conditions for the leading-order
Ostrovsky equations by construction have zero mass. Thus, the so-called
"zero-mass contradiction" has been completely by-passed.

13
The categories of this paper are: quant-ph
4
The categories of this paper are: cond-mat
10
The categories of this paper are: q-bio
37
The categories of this paper are: supr-con
19
The categories of this paper are: eess
29
The categories of this paper are: funct-an
0
The categories of this paper are: hep-ph
15
The categories of this paper are: nucl-ex
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The categories of this paper are: econ
5
The categories of this paper are: gr-qc
7
The categories of this paper are: hep-th
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The categories of this paper are: solv-int
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The categories of this paper are: ao-sci
30
The categories of this paper are: q-alg
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The categories of this paper are: bayes-an
1
The categories of this paper are: cs