Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Critical points of solutions of degenerate elliptic equations in the
  plane   We study the minimizer u of a convex functional in the plane which is not
G\^ateaux-differentiable. Namely, we show that the set of critical points of
any C^1-smooth minimizer can not have isolated points. Also, by means of some
appropriate approximating scheme and viscosity solutions, we determine an
Euler-Lagrange equation that u must satisfy. By applying the same approximating
scheme, we can pair u with a function v which may be regarded as the stream
function of u in a suitable generalized sense.

14
The categories of this paper are: math-ph
28
The categories of this paper are: alg-geom
29
The categories of this paper are: funct-an
1
The categories of this paper are: cs
18
The categories of this paper are: econ
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
26
The categories of this paper are: bayes-an
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
23
The categories of this paper are: solv-int
33
The categories of this paper are: plasm-ph
12
The categories of this paper are: nucl-th
31
The categories of this paper are: ao-sci
20
The categories of this paper are: acc-phys
10
The categories of this paper are: q-bio