Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: A pocket guide to nonlinear differential equations in the
  Musielak--Orlicz spaces   The Musielak--Orlicz setting unifies the variable exponent, Orlicz, weighted
Sobolev, and double-phase spaces. They inherit technical difficulties resulting
from general growth and inhomogeneity. In this survey we present an overview of
developments of the theory of existence of~PDEs in the setting including
reflexive and non-reflexive cases, as well as isotropic and anisotropic ones.
Particular attention is paid to problems with data below natural duality in
absence of Lavrentiev's phenomenon.

33
The categories of this paper are: plasm-ph
31
The categories of this paper are: ao-sci
17
The categories of this paper are: q-fin
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
21
The categories of this paper are: adap-org
24
The categories of this paper are: dg-ga
4
The categories of this paper are: cond-mat
12
The categories of this paper are: nucl-th
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
26
The categories of this paper are: bayes-an
20
The categories of this paper are: acc-phys
9
The categories of this paper are: nlin
34
The categories of this paper are: chem-ph