Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: On solutions of a Boussinesq-type equation with displacement-dependent
  nonlinearity: a soliton doublet   In this paper the permanent profile waves governed by a Boussinesq-type wave
equation are analysed. The model involves displacement-type nonlinearities and
dispersion terms. Physically such a model equation describes longitudinal waves
(density change) in biomembranes which have an internal structure composed by
lipid molecules. The possible solutions are constructed and analysed. The phase
plane analysis and numerical simulation reveal a novel phenomenon: the possible
existence of a soliton doublet.

13
The categories of this paper are: quant-ph
37
The categories of this paper are: supr-con
8
The categories of this paper are: hep-ex
31
The categories of this paper are: ao-sci
12
The categories of this paper are: nucl-th
1
The categories of this paper are: cs
29
The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
33
The categories of this paper are: plasm-ph
30
The categories of this paper are: q-alg
16
The categories of this paper are: stat
25
The categories of this paper are: patt-sol
28
The categories of this paper are: alg-geom
22
The categories of this paper are: chao-dyn
15
The categories of this paper are: nucl-ex
3
The categories of this paper are: physics