Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Surfaces with Parallel Normalized Mean Curvature Vector Field in
  Euclidean or Minkowski 4-Space   We study surfaces with parallel normalized mean curvature vector field in
Euclidean or Minkowski 4-space. On any such surface we introduce special
isothermal parameters (canonical parameters) and describe these surfaces in
terms of three invariant functions.
  We prove that any surface with parallel normalized mean curvature vector
field parametrized by canonical parameters is determined uniquely up to a
motion in Euclidean (or Minkowski) space by the three invariant functions
satisfying a system of three partial differential equations. We find examples
of surfaces with parallel normalized mean curvature vector field and solutions
to the corresponding systems of PDEs in Euclidean or Minkowski space in the
class of the meridian surfaces.

8
The categories of this paper are: hep-ex
1
The categories of this paper are: cs
7
The categories of this paper are: hep-th
9
The categories of this paper are: nlin
24
The categories of this paper are: dg-ga
36
The categories of this paper are: cmp-lg
13
The categories of this paper are: quant-ph
34
The categories of this paper are: chem-ph
30
The categories of this paper are: q-alg
33
The categories of this paper are: plasm-ph
3
The categories of this paper are: physics
12
The categories of this paper are: nucl-th
16
The categories of this paper are: stat
0
The categories of this paper are: hep-ph
18
The categories of this paper are: econ
25
The categories of this paper are: patt-sol