Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Nonplanar ancient curve shortening flows in $\mathbb{R}^3$ from grim
  reapers   In this note we construct new nonplanar ancient (in fact, eternal) solutions
to the curve shortening flow in $\mathbb{R}^3$, built out of translating grim
reapers laying in perpendicular planes.

32
The categories of this paper are: atom-ph
16
The categories of this paper are: stat
36
The categories of this paper are: cmp-lg
25
The categories of this paper are: patt-sol
15
The categories of this paper are: nucl-ex
18
The categories of this paper are: econ
0
The categories of this paper are: hep-ph
19
The categories of this paper are: eess
33
The categories of this paper are: plasm-ph
20
The categories of this paper are: acc-phys
22
The categories of this paper are: chao-dyn
12
The categories of this paper are: nucl-th
35
The categories of this paper are: mtrl-th
9
The categories of this paper are: nlin
3
The categories of this paper are: physics
4
The categories of this paper are: cond-mat